Pith. sign in

REVIEW 4 major objections 5 minor 126 references

Cassiopeia A's Reverse Shock and its Effects on the Expanding SN Ejecta

T0 review · 4 major / 5 minor · reviewed 2026-08-10 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

Pith's one-line read Seven decades of optical images show that Cassiopeia A's reverse shock moves outward at 1000-2000 km/s, about 1000 km/s slower than X-ray estimates, and is nearly stationary along the western limb.

desk verdict A genuinely useful optical proper-motion survey of Cas A's reverse shock, conditional on an unquantified brightening-delay systematic and an overstated western-limb claim. read the letter →

arxiv 2501.07708 v1 pith:3BFBBDVU submitted 2025-01-13 astro-ph.HE

Robert A. Fesen , Dan Milisavljevic , Daniel Patnaude , Roger A. Chevalier , John C. Raymond , McKinley Brumback , Kathryn E. Weil This is my paper · ORCID
classification astro-ph.HE
keywords CassiopeiaAsupernovaremnantreverseshockejectapropermotionsmassablationopticalimagingX-rayversusvelocitiescore-collapse
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper uses optical and near-infrared images of the Cassiopeia A supernova remnant taken between 1951 and 2022, plus spectra of selected filaments, to track the motion of the remnant's reverse shock by watching where new optical ejecta brighten. The authors argue that the reverse shock is advancing outward at roughly 1000-2000 km/s over most of the main shell, about 1000 km/s slower than recent X-ray measurements imply, and that along the western limb it is nearly stationary in the sky frame rather than moving inward at about 2000 km/s. If right, this changes the picture of how fast the inner shock is moving through the ejecta and lowers the relative shock speeds that heat and destroy the remnant's metal-rich knots. The paper also finds that ejecta knots suffer mass ablation into trailing tails, seen best in high-ionization lines, while their dense cores decelerate very little.

What carries the argument

The central object is the base of newly brightened optical ejecta, especially the P1 northeast ejecta stream, whose starting point is identified as the reverse shock front. The method works by aligning multi-epoch HST and ground-based images in the expanding ejecta's rest frame and measuring the proper motion of newly appearing emission relative to outward-moving knots; subtracting the ejecta's sky-frame motion gives the reverse shock's velocity in the sky frame. The identification relies on the claim that optical ejecta become visible within about a year of shock passage, so the first brightening location approximates the shock front's position to sub-arcsecond precision.

What would settle it

A high-cadence monitoring campaign that catches the same ejecta knot turn on in the optical within months, while independently locating the reverse shock front at that time from contemporaneous X-ray or radio images, would test whether the first-appearance base tracks the shock front; a measured delay of several years would shift the inferred reverse shock positions and velocities. A second check is re-measuring the P1 stream's base brightness across the 1951-1999 plates, since a varying base intensity would break the assumption of a constant, identifiable base location.

Watch

Extended reading notes

Core claim

The paper's central claim is that the sequence of optical ejecta brightening, the appearance of freshly shocked knots at the base of expanding streams, tracks the reverse shock front, and that front moves outward in the observer's sky frame at typically 1000 to 2000 km/s across the main shell, not at the roughly 2000 to 4000 km/s speeds inferred from X-ray proper motions. At the western limb, the optical data show the front is close to stationary in the sky frame, with a best value near zero and no evidence for the roughly 1900 km/s inward motion reported from X-rays. The same measurements give outward tangential ejecta motions of 3500 to 6000 km/s, with slower values in the south, and post-shock knots display 0.2 to 0.5 arcsecond ablation tails whose low-density material is decelerated by up to about 1000 km/s while the dense cores stay close to free expansion with a deceleration parameter of 0.95 to 0.99.

Load-bearing premise

The measurement assumes that an ejecta knot's first brightening marks the reverse shock front's location at that epoch, with a brightening delay of roughly one year or less; if the delay is longer or a knot's internal density shifts where the brightening appears, the measured motion of the base is not the reverse shock's true velocity.

Editorial extensions

If this is right

  • Most of Cas A's main shell experiences reverse shock speeds of 1000 to 2000 km/s in the sky frame, roughly 1000 km/s slower than recent X-ray values and below the 2000 to 4000 km/s speeds predicted by hydrodynamic models.
  • Along the western limb the reverse shock is nearly stationary in the sky frame, so western ejecta still encounter it at a high relative speed of about 5500 to 5800 km/s because the ejecta themselves are moving outward fast, but there is no need for an inward-plunging shock.
  • Ejecta knots are not strongly decelerated as a whole: dense cores keep a deceleration parameter of 0.95 to 0.99, near free expansion, while lower-density ablated material is decelerated by up to about 1000 km/s and appears as trailing tails in lines such as [O III] and [S III].
  • Slower southern ejecta motions of 3500 to 5000 km/s may explain why Cas A's southern rim is fainter and evolves more slowly than the north, where speeds reach 5500 to 6000 km/s.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Inference: if the roughly one-year brightening delay is correct, aligned X-ray and optical images taken at the same epoch should show the optical turn-on front at a slightly smaller radius than the X-ray reverse shock shell, with an offset equal to ejecta speed times the delay; measuring that offset would directly test the identification.
  • Inference: the lack of unusually high-ionization optical lines in western ejecta, despite the high relative shock speeds implied by the X-ray inward motion, suggests the western X-ray synchrotron filaments may need an explanation other than a fast inward reverse shock, such as a distorted or projected shock front.
  • Inference: because dense knot cores decelerate so little, most ejecta mass may continue in nearly free expansion while only low-density envelopes are stripped; distinguishing these two components could refine models of dust destruction and metal mixing into the surrounding medium.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. This paper uses optical and near-infrared images of Cassiopeia A spanning 1951–2022, together with optical spectra, to measure the motion of the reverse shock through the remnant's main shell. The authors identify the sequential brightening of ejecta knots with the advancement of the reverse shock in the ejecta frame, and from the difference between this and the measured ejecta proper motions they derive sky-frame reverse shock velocities at 15 positions. They report typical reverse shock velocities of 1000–2000 km/s, about 1000 km/s lower than recent X-ray estimates, and a nearly stationary or only slowly moving reverse shock along the western limb, contradicting the inward motion of ~1900 km/s reported by Vink et al. (2022). They also present HST and JWST images showing ablated ejecta tails and spectroscopic evidence for ~500–1000 km/s deceleration of ablated material.

Significance. If the central velocity claim holds, the paper provides an important optical anchor for the reverse shock velocity in Cas A and sharpens the discrepancy between optical and X-ray measurements, with implications for the western limb's synchrotron emission and for reverse shock models. The paper's strengths include the assembly of a unique multi-epoch dataset, including digitized Palomar plates, HST, and JWST images, and the explicit public archiving of the digitized plates. The measurements are reported with error bars and with candid discussion of difficult regions, which is commendable. However, the headline result rests on an uncalibrated assumption about the brightening delay of main-shell ejecta after reverse shock passage, and on several positions that the authors themselves describe as 'seriously subjective.' These issues do not invalidate the dataset but they are load-bearing for the paper's main claim, and they need to be addressed before the velocity numbers can be taken at face value.

major comments (4)
  1. [§3.2.3 and Table 5] The identification of the first appearance of optical emission with the reverse shock location at that epoch assumes that the brightening delay τ is about one year or less for main-shell O/S/Ar/Ca ejecta. The only quantitative constraint cited, the <9-month turn-on of outer [N II] knots (Fesen et al. 2011), is explicitly acknowledged to come from chemically and dynamically distinct ejecta. The paper gives no observational or modeling constraint on τ for the main-shell knots, and the quoted 10–20 yr shock-crossing time for 0.1" knots at 100 km/s suggests that the cooling/ionization front may take substantially longer than one year to brighten. If τ ≈ 5–10 yr, then the proper motion measured in the ejecta frame (Table 5, column 7) tracks the brightening front rather than the reverse shock, and the sky-frame velocities in column 9 are biased; for V_RS ~1500 km/s and τ = 5 yr the offset is ~0.5", comparable to the reported advances. The paper should quantify this systematic error, for example by treating τ as a free parameter and plotting V_RS(τ), or by using radiative-shock models for main-shell densities. Without such an analysis, the headline '1000–2000 km/s' is conditional on an unverified assumption.
  2. [§4.7, Abstract, and Conclusions] The text in §4.7 states that the P12 measurement is 'not sufficient to firmly reject a value as large as ≈0.41″' (the value attributed to Vink et al. 2022), yet the abstract asserts 'we do not find the reverse shock to move inward at velocities as large as ~2000 km/s as has been reported' and conclusion (2) says 'we do not find evidence for high velocity inward reverse shock motions.' These statements are stronger than the measurement supports. In addition, the quoted '≈0.41″' is inconsistent with the Vink et al. (2022) value listed in Table 3 (−0.1167″/yr; −1880 km/s), and the source of 0.41″ should be clarified. The abstract and conclusions should be brought into line with the actual uncertainty, for example by stating that the optical western-limb data are consistent with a nearly stationary reverse shock but cannot exclude the Vink et al. inward value at high significance.
  3. [§4.5 and Table 5] The reverse shock velocities at P7, P8, and P9 are described as 'seriously subjective' and 'particularly challenging,' yet these three points carry some of the lowest sky-frame velocities in Table 5 (1020–1460 km/s) and are central to the claim that southern ejecta experience slower reverse shock velocities. A robustness check that recomputes the headline velocity range after removing or downweighting these three subjective positions should be presented; if the 1000–2000 km/s claim depends on them, the text should say so explicitly. As written, the summary statement 'typically 1000–2000 km/s over most of the remnant' is partly supported by measurements that the authors themselves caution should be taken with caution.
  4. [§4.1] The P1 measurement assumes that the intensity of the streak's base did not vary significantly over the nearly 50-year baseline, and that the base marks the reverse shock location. The authors note that after 1980 the base shifts southward as the stream loses its radial orientation; this raises the possibility that the apparent base motion of 0.078″/yr is at least partly a geometric effect of viewing a delayed brightening front rather than a clean reverse shock motion. The 1951–1999 Palomar data are a unique resource, but the constant-intensity assumption should be tested, e.g., by measuring the base position with a more explicit model of the stream orientation and by comparing the base motion to the motion of the brightening front in more recent epochs.
minor comments (5)
  1. [§4.6] The sentence 'this gave consistent results across both P10 and P10 regions' should read 'P10 and P11 regions.'
  2. [§4.7] The phrase 'transverse velocity ∼1000' is missing units; it should read '∼1000 km/s' (or '−1000 km/s') when referring to Vink et al.'s western-limb reverse shock motion.
  3. [Figure 2 caption] The caption refers to 'Table 2 for details' but the observation log is in Table 4; please update the cross-reference.
  4. [§3.2.2] The phrase 'creating a discontinuous brightening process at times for even for seemingly adjacent ejecta knots' contains a doubled 'for'; please reword.
  5. [§2.1] The sentence 'Multi-passband HST images of Cas A were obtained at several epochs using the Wide Field Planetary Camera 2 (WFPC2) starting in 1999 and ending in 2008' is grammatically awkward; consider revising for clarity.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the reverse-shock velocities are derived from measured proper motions, not from fitted parameters or self-referential definitions.

full rationale

The paper's central claim is an observational measurement, not a derivation from a fitted model. The reverse-shock sky-frame velocities in Table 5 are computed as the difference between measured ejecta proper motions and measured brightening-front proper motions in the ejecta frame (V_RS^sky = V_ejecta^sky - V_RS^ejecta), which is a kinematic identity, not a circular reduction. The identification of newly brightened optical emission with the reverse-shock front involves a physical assumption that the post-shock brightening delay is about one year; the paper states this delay is 'not firmly established observationally' and is 'likely a function of knot density and reverse shock velocity' (Section 3.2.3). That is a systematic-uncertainty concern, but it is not an input that is later renamed as the output. No fitted parameter is presented as a prediction. Self-citations (e.g., Milisavljevic & Fesen 2013 radial-velocity catalog, Morse et al. 2004, Fesen et al. 2011) are used as reference data or comparison points; the paper explicitly notes that the outer [N II] knots with sub-9-month turn-on are chemically distinct from main-shell O/S/Ar/Ca ejecta, so that citation is not quietly importing the central assumption. No uniqueness theorem or ansatz is smuggled in via citation, and the disagreement with Vink et al. (2022) rests on independent optical proper motions, not on the authors' own prior result.

Assumptions & free parameters 0 free parameters · 5 assumptions · 0 invented entities

The paper introduces no new physical entities and fits no free parameters to data. Its central measurements rely on the standard distance and expansion-center priors, plus a set of observational assumptions about the link between optical brightening and the reverse shock front. The most fragile input is the ad hoc identification of the P1 stream base as the reverse shock, and the unquantified brightening-delay assumption.

assumptions (5)
  • domain assumption Distance to Cas A is 3.4 kpc.
    Used throughout to convert proper motions to velocities (Table 5 and text); value taken from prior literature (Reed et al. 1995; Alarie et al. 2014; Neumann et al. 2024).
  • domain assumption The center of expansion and explosion epoch are as determined by Thorstensen et al. (2001).
    Used to define position angles, radial distances, and the expansion parameter m (Section 4).
  • domain assumption Optical brightening of ejecta follows reverse shock passage within about one year.
    Supports the identification of the base of new emission with the reverse shock location; discussed in Section 3.2.3 with reference to Morse et al. (2004), but not independently measured here.
  • domain assumption Radial velocities from Milisavljevic & Fesen (2013) are accurate for the measured knots.
    Used to convert transverse reverse shock velocities to space velocities for specific positions (Sections 4.1 and 6.1).
  • ad hoc to paper The base of the P1 ejecta stream marks the reverse shock and its intensity remained stable over 50 years.
    Section 4.1 assumes the stream's starting point is the reverse shock location and that its brightness did not vary significantly, underpinning the P1 reverse shock velocity of 1260 km/s.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Cassiopeia A's Reverse Shock and its Effects on the Expanding SN Ejecta." pith.science (2026). https://pith.science/paper/3BFBBDVU

@misc{pith2026250107708,
  author       = {Pith},
  title        = {Pith review of: Cassiopeia A's Reverse Shock and its Effects on the Expanding SN Ejecta},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/3BFBBDVU}},
  note         = {Machine review of arXiv:2501.07708}
}
read the original abstract

Using optical and near-infrared images of the Cassiopeia A (Cas A) supernova remnant covering the time period 1951 to 2022, together with optical spectra of selected filaments, we present an investigation of Cas A's reverse shock velocity and the effects it has on the remnant's metal-rich ejecta. We find the sequence of optical ejecta brightening and the appearance of new optical ejecta indicating the advancement of the remnant's reverse shock in the remnant's main shell has velocities typically between 1000 and 2000 km/s, which is ~1000 km/s less than recent measurements made in X-rays. We further find the reverse shock appears to move much more slowly and is nearly even stationary in the sky frame along the remnant's western limb. However, we do not find the reverse shock to move inward at velocities as large as ~2000 km/s as has been reported. Optical ejecta in Cas A's main emission shell have proper motions indicating outward tangential motions ~3500 - 6000 km/s, with the smaller values preferentially along the remnant's southern regions which we speculate may be partially the cause of the remnant's faint and more slowly evolving southern sections. Following interaction with the reverse shock, ejecta knots exhibit extended mass ablated trails 0.2" - 0.5" in length leading to extended emission indicating reverse shock induced decelerated velocities as large as 1000 km/s. Such ablated material is most prominently seen in higher ionization line emissions, whereas denser parts of ejecta knots show surprisingly little deceleration.

Figures

Figures reproduced from arXiv: 2501.07708 by the authors.

Figure 1
Figure 1. Comparison of Cas A’s large-scale optical (HST), radio (VLA), infrared (Spitzer) and X-ray (Chandra) emissions. The dashed black circles are 160′′ in radius and centered on the remnant’s expansion center (Thorstensen et al. 2001; α(J2000) = 23h 23m 27.77s , δ(J2000) = 58◦ 48′ 49.4 ′′) marked as a small cross in the optical and X-ray images. The dashed circles show the extent of the remnant’s outermost radio and infr… view at source ↗
Figure 2
Figure 2. Seventy years of evolution of Cas A’s red optical emission between 1951 and 2021. Images between 1951 and 1976 are digitally scanned broadband red Palomar 5m plates, 1992 and 2021 are CCD MDM 2.4m images, with the 2004 and 2011 images red and near-IR HST images (see [PITH_FULL_IMAGE:figures/full_fig_p008_2.png] view at source ↗
Figure 3
Figure 3. Evolution of Cas A’s southern optical emission. Circles shown are 115′′ in radius centered on the center of expansion of Cas A’s radio emission knots and shell (Ander￾son & Rudnick 1995). Note the southern’s limb spherical morphology present in 2021. North is up, East to the left. 3. OVERVIEW OF CAS A’S EMISSIONS Until the realization of the existence and role of Cas A’s reverse shock in the mid-1970’s, changes in t… view at source ↗
Figures from the paper (17 more)
Figure 4
Figure 4. Figure 4: Comparison of 2000 and 2019 red HST images of exactly the same 80′′ × 50′′ northwest region illustrating large changes in Cas A’s optical morphology over a 19 year period. North is up and East is left [PITH_FULL_IMAGE:figures/full_fig_p010_4.png]
Figure 5
Figure 5. Figure 5: January 2000 and January 2002 WFC2 images, and a March 2004 ACS HST WFC2 image of ejecta in Cas A’s north regions showing ejecta brightness changes due to the reverse shock. Images are shown centered on the expanding ejecta. Circles in the top two panels are 4” in radi…
Figure 6
Figure 6. Figure 6: Top panel: A December 2004 HST image of the Cas A’s northern portion covering the remnant’s two large rings of optically bright ejecta. Bottom panel: A mosaic January 2000 and December 2004 difference images made comparing the 2004 image (black) with the 2000 image (wh…
Figure 7
Figure 7. Figure 7: Combined March 2004 HST ACS F625W and F775W images of Cas A showing locations where reverse shock velocity measurements were made. The black cross marks the remnant’s optical center of expansion (Thorstensen et al. 2001.) tions of the Jan 2000 and Dec 2004 images were …
Figure 8
Figure 8. Figure 8: P1: A coherent stream of ejecta located in the northeast region of Cas A is shown here as it evolves in ground-based images taken between 1951 and 1999. Ejecta in this stream becomes sequentially visible through interaction with Cas A’s slower expanding reverse shock f…
Figure 9
Figure 9. Figure 9: Examples of the appearance of new emission features along Cas A’s eastern limb reflecting the motion of the reverse shock at Positions P2, P3, and P4. Images as shown are in the rest frame of the ejecta which are moving to the left (eastward); The slower expanding reve…
Figure 10
Figure 10. Figure 10: December 2004 ACS/WFC F625W+F775W and November WFC3 F980M 2011 images of Cas A’s southeastern limb showing locations of P5 and P6. in the rest frame of the expanding ejecta. The appearance of new emission within the red boxes (6′′ × 6 ′′) is due to the proper motion o…
Figure 11
Figure 11. Figure 11: January 2000 WFC2 F675W, December 2004 ACS/WFC F6225W+F775W, November 2010 WFC3 F980M and November 2011 WFC3 F980M images of Cas A’s southern limb showing the locations of P7, P8, and P9. Images are shown in the rest frame of the expanding ejecta. The appearance of ne…
Figure 12
Figure 12. Figure 12: March 2004 ACS/WFC F850LP and November 2011 WFC3 F980M images of Cas A’s southwestern limb showing the locations of P10 and P11. Images are shown in the rest frame of the expanding ejecta. The appearance of new emission features (white) inside the red boxes (6′′ × 6 ′…
Figure 13
Figure 13. Figure 13: March 2004 ACS/WFC F850LP and November 2011 WFC3 F980M images of Cas A’s western limb showing the location of P12 in the sky frame. The appearance of new emission features (white) inside the red boxes between 2004 and 2011 (10′′ × 10′′) is due to the proper motion of …
Figure 14
Figure 14. Figure 14: January 2000 WFC2 F675W, December 2004 ACS/WFC F6225W+F775W, and June 2008 WFC2 F675W of Cas A’s northwestern limb showing the locations of the P13, P14, and P15 regions. Images are shown in the rest frame of the expanding ejecta. The appearance of new emission in the…
Figure 15
Figure 15. Figure 15: Evolution of Cas A’s optical emission along its northwestern limb. celeration differences which can be seen in high resolu￾tion images where recently reverse shocked ejecta show elongated shapes and trailing ablation tails. Observ￾able structural and emission changes …
Figure 16
Figure 16. Figure 16: Combined HST ACS/WFC 2022 November 27 F625W + F775W filter images of four northern regions exhibiting radially distorted ejecta morphology due to interaction with the reverse shock. Top panel shows the location of the four enlarged regions. Middle panels: East and Wes…
Figure 17
Figure 17. Figure 17: Combined HST ACS/WFC 2004 March 04 F625W + F775W filter images of four southern regions exhibiting distorted ejecta morphologies following interaction with the reverse shock. Top panel shows the location of the four enlarged regions. Middle panels: southeast and south…
Figure 18
Figure 18. Figure 18: Top left panel - Reference image where the locations of the three slits used and the knots studied are indicated. Top right panel - The spectrum from Slit 1’s spectrum shows Knot 1’s [O III] λλ 4959,5007 emissions. Marked by the black arrow, Knot 1 has a radial veloci…
Figure 19
Figure 19. Figure 19: High resolution JWST [Fe II] F162M images of ejecta showing fine scale ejecta knot morphologies along Cas A’s northeast and northwest regions (top panels) and its southern limb (bottom panel). North is up, East is to the left. Comparison of photographic plates taken o…
Figure 20
Figure 20. Figure 20: Comparison of our optically estimated vs. X-ray inferred reverse shock velocities made by Vink et al. (2022) using their velocity plots for values in the sky frame (left panel) and in the ejecta’s reference frame (right panel). The black line and black points are the …

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

126 extracted references · 48 canonical work pages

  1. [1]

    , " * write output.state after.block = add.period write newline

    ENTRY address archivePrefix author booktitle chapter doi edition editor eprint howpublished institution journal key month number organization pages publisher school series title misctitle type volume year version url label extra.label sort.label short.list INTEGERS output.state before.all mid.sentence after.sentence after.block FUNCTION init.state.consts ...

  2. [2]

    write newline

    " write newline "" before.all 'output.state := FUNCTION format.url url empty "" new.block "" url * "" * if FUNCTION format.eprint eprint empty "" archivePrefix empty "" archivePrefix "arXiv" = new.block " " eprint * " " * new.block " " eprint * " " * if if if FUNCTION format.doi doi empty "" " " doi * " " * if FUNCTION format.pid doi empty eprint empty ur...

  3. [3]

    ,# (7),01444 '9=82<.342C 2! !22222222222222222222222222222222222222222222222222

    thebibliography [1] 20pt to REFERENCES 6pt =0pt 10pt plus 3pt =0pt =0pt =1pt plus 1pt =0pt =0pt -12pt =13pt plus 1pt =20pt =13pt plus 1pt \@M =10000 =-1.0em =0pt =0pt 0pt =0pt =1.0em @enumiv\@empty 10000 10000 `\.\@m \@noitemerr \@latex@warning Empty `thebibliography' environment \@ifnextchar \@reference \@latexerr Missing key on reference command Each re...

    2019

  4. [4]

    2014, , 441, 2996, 10.1093/mnras/stu774

    Alarie , A., Bilodeau , A., & Drissen , L. 2014, , 441, 2996, 10.1093/mnras/stu774

    doi:10.1093/mnras/stu774 2014

  5. [5]

    C., & Rudnick , L

    Anderson , M. C., & Rudnick , L. 1995, , 441, 307, 10.1086/175357

    work page doi:10.1086/175357 1995

  6. [6]

    2018, , 612, A110, 10.1051/0004-6361/201732411

    Arias , M., Vink , J., de Gasperin , F., et al. 2018, , 612, A110, 10.1051/0004-6361/201732411

    doi:10.1051/0004-6361/201732411 2018

  7. [7]

    1954, , 119, 206, 10.1086/145812

    Baade , W., & Minkowski , R. 1954, , 119, 206, 10.1086/145812

    doi:10.1086/145812 1954

  8. [8]

    A., & Krause , O

    Besel , M. A., & Krause , O. 2012, , 541, L3, 10.1051/0004-6361/201219082

    doi:10.1051/0004-6361/201219082 2012

Show all 126 references
  1. [9]

    R., Bohlin , R

    Boffi , F. R., Bohlin , R. C., McLean , D. F., & Pavlovsky , C. M. 2003, Baseline Tests for the Advanced Camera for Surveys Astronomer's Proposal Tool Exposure Time Calculator , Instrument Science Report ACS 2003-008

    2003

  2. [10]

    Chevalier , R. A. 1977, , 15, 175, 10.1146/annurev.aa.15.090177.001135

    1977

  3. [11]

    1982, , 258, 790, 10.1086/160126

    ---. 1982, , 258, 790, 10.1086/160126

    1982 doi

  4. [12]

    A., & Kirshner , R

    Chevalier , R. A., & Kirshner , R. P. 1978, , 219, 931, 10.1086/155855

    1978 doi

  5. [13]

    1979, , 233, 154, 10.1086/157377

    ---. 1979, , 233, 154, 10.1086/157377

    1979 doi

  6. [14]

    A., & Oishi , J

    Chevalier , R. A., & Oishi , J. 2003, , 593, L23, 10.1086/377572

    2003 doi

  7. [15]

    2024, , 976, L4, 10.3847/2041-8213/ad855d

    De Looze , I., Milisavljevic , D., Temim , T., et al. 2024, , 976, L4, 10.3847/2041-8213/ad855d

    2024 doi

  8. [16]

    2003, , 589, 818, 10.1086/374813

    DeLaney , T., & Rudnick , L. 2003, , 589, 818, 10.1086/374813

    2003 doi

  9. [17]

    D., et al

    DeLaney , T., Rudnick , L., Stage , M. D., et al. 2010, , 725, 2038, 10.1088/0004-637X/725/2/2038

    2010 doi

  10. [18]

    Fesen , R. A. 2001, , 133, 161, 10.1086/319181

    2001 doi

  11. [19]

    A., Becker , R

    Fesen , R. A., Becker , R. H., & Blair , W. P. 1987, , 313, 378, 10.1086/164974

    1987 doi

  12. [20]

    A., Becker , R

    Fesen , R. A., Becker , R. H., & Goodrich , R. W. 1988, , 329, L89, 10.1086/185183

    1988 doi

  13. [21]

    A., & Milisavljevic , D

    Fesen , R. A., & Milisavljevic , D. 2016, , 818, 17, 10.3847/0004-637X/818/1/17

    2016 doi

  14. [22]

    A., Morse , J

    Fesen , R. A., Morse , J. A., Chevalier , R. A., et al. 2001, , 122, 2644, 10.1086/323539

    2001 doi

  15. [23]

    A., Zastrow , J

    Fesen , R. A., Zastrow , J. A., Hammell , M. C., Shull , J. M., & Silvia , D. W. 2011, , 736, 109, 10.1088/0004-637X/736/2/109

    2011 doi

  16. [24]

    A., Hammell , M

    Fesen , R. A., Hammell , M. C., Morse , J., et al. 2006 a , , 645, 283, 10.1086/504254

    2006 doi

  17. [25]

    2006 b , , 636, 859, 10.1086/498092

    ---. 2006 b , , 636, 859, 10.1086/498092

    2006 doi

  18. [26]

    C., Bartko , F., Bely , P

    Ford , H. C., Bartko , F., Bely , P. Y., et al. 1998, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 3356, Space Telescopes and Instruments V, ed. P. Y. Bely & J. B. Breckinridge , 234--248, 10.1117/12.324464

    1998 doi

  19. [27]

    1991, , 367, 619, 10.1086/169657

    Fryxell , B., Mueller , E., & Arnett , D. 1991, , 367, 619, 10.1086/169657

    1991 doi

  20. [28]

    V., Koralesky , B., Rudnick , L., et al

    Gotthelf , E. V., Koralesky , B., Rudnick , L., et al. 2001, , 552, L39, 10.1086/320250

    2001 doi

  21. [29]

    Gull , S. F. 1975, , 171, 263, 10.1093/mnras/171.2.263

    1975 doi

  22. [30]

    C., & Fesen , R

    Hammell , M. C., & Fesen , R. A. 2008, , 179, 195, 10.1086/591528

    2008 doi

  23. [31]

    J., Janka , H

    Hammer , N. J., Janka , H. T., & M \"u ller , E. 2010, , 714, 1371, 10.1088/0004-637X/714/2/1371

    2010 doi

  24. [32]

    C., Frank , A., Hartigan , P., & Lebedev , S

    Hansen , E. C., Frank , A., Hartigan , P., & Lebedev , S. V. 2017, , 837, 143, 10.3847/1538-4357/aa5ca8

    2017 doi

  25. [33]

    A., & Vink , J

    Helder , E. A., & Vink , J. 2008, , 686, 1094, 10.1086/591242

    2008 doi

  26. [34]

    A., & Miller , W

    Hoag , A. A., & Miller , W. C. 1969, , 8, 2417, 10.1364/AO.8.002417

    1969 doi

  27. [35]

    A., & Auchettl , K

    Holland-Ashford , T., Lopez , L. A., & Auchettl , K. 2020, , 889, 144, 10.3847/1538-4357/ab64e4

    2020 doi

  28. [36]

    Hughes , J. P. 2000, , 545, L53, 10.1086/317337

    2000 doi

  29. [37]

    P., & Fesen , R

    Hurford , A. P., & Fesen , R. A. 1996, , 469, 246, 10.1086/177775

    1996 doi

  30. [38]

    S., & Petre , R

    Hwang , U., Holt , S. S., & Petre , R. 2000, , 537, L119, 10.1086/312776

    2000 doi

  31. [39]

    Hwang , U., & Laming , J. M. 2012, , 746, 130, 10.1088/0004-637X/746/2/130

    2012 doi

  32. [40]

    A., & Mandel , E

    Joye , W. A., & Mandel , E. 2003, in Astronomical Society of the Pacific Conference Series, Vol. 295, Astronomical Data Analysis Software and Systems XII, ed. H. E. Payne , R. I. Jedrzejewski , & R. N. Hook , 489

    2003

  33. [41]

    1976 a , , 51, 236

    Kamper , K., & van den Bergh , S. 1976 a , , 51, 236

    1976

  34. [42]

    1976 b , , 32, 351, 10.1086/190400

    ---. 1976 b , , 32, 351, 10.1086/190400

    1976 doi

  35. [43]

    2018, , 856, 18, 10.3847/1538-4357/aab092

    Katsuda , S., Morii , M., Janka , H.-T., et al. 2018, , 856, 18, 10.3847/1538-4357/aab092

    2018 doi

  36. [44]

    E., Do , T., de Mink , S

    Kerzendorf , W. E., Do , T., de Mink , S. E., et al. 2019, , 623, A34, 10.1051/0004-6361/201732206

    2019 doi

  37. [45]

    T., & M \"u ller , E

    Kifonidis , K., Plewa , T., Janka , H. T., & M \"u ller , E. 2003, , 408, 621, 10.1051/0004-6361:20030863

    2003 doi

  38. [46]

    S., De Looze , I., et al

    Kirchschlager , F., Sartorio , N. S., De Looze , I., et al. 2024, , 528, 5364, 10.1093/mnras/stae365

    2024 doi

  39. [47]

    D., Barlow , M

    Kirchschlager , F., Schmidt , F. D., Barlow , M. J., De Looze , I., & Sartorio , N. S. 2023, , 520, 5042, 10.1093/mnras/stad290

    2023 doi

  40. [48]

    D., Barlow , M

    Kirchschlager , F., Schmidt , F. D., Barlow , M. J., et al. 2019, , 489, 4465, 10.1093/mnras/stz2399

    2019 doi

  41. [49]

    I., McKee , C

    Klein , R. I., McKee , C. F., & Colella , P. 1994, , 420, 213, 10.1086/173554

    1994 doi

  42. [50]

    2018, , 866, 139, 10.3847/1538-4357/aae20e

    Koo , B.-C., Kim , H.-J., Lee , Y.-H., et al. 2018, , 866, 139, 10.3847/1538-4357/aae20e

    2018 doi

  43. [51]

    V., & Keohane , J

    Koralesky , B., Rudnick , L., Gotthelf , E. V., & Keohane , J. W. 1998, , 505, L27, 10.1086/311604

    1998 doi

  44. [52]

    M., Usuda , T., et al

    Krause , O., Birkmann , S. M., Usuda , T., et al. 2008, Science, 320, 1195, 10.1126/science.1155788

    2008 doi

  45. [53]

    M., & Hwang , U

    Laming , J. M., & Hwang , U. 2003, , 597, 347, 10.1086/378268

    2003 doi

  46. [54]

    Latham , D. W. 1974, Methods of Experimental Physics, 12, 221, 10.1016/S0076-695X(08)60497-4

    1974 doi

  47. [55]

    S., MacAlpine , G

    Lawrence , S. S., MacAlpine , G. M., Uomoto , A., et al. 1995, , 109, 2635, 10.1086/117477

    1995 doi

  48. [56]

    2010, , 140, 1062, 10.1088/0004-6256/140/4/1062

    Laycock , S., Tang , S., Grindlay , J., et al. 2010, , 140, 1062, 10.1088/0004-6256/140/4/1062

    2010 doi

  49. [57]

    P., & Slane , P

    Lee , J.-J., Park , S., Hughes , J. P., & Slane , P. O. 2014, , 789, 7, 10.1088/0004-637X/789/1/7

    2014 doi

  50. [58]

    F., Klein , R

    Mac Low , M.-M., McKee , C. F., Klein , R. I., Stone , J. M., & Norman , M. L. 1994, , 433, 757, 10.1086/174685

    1994 doi

  51. [59]

    D., & McKee , C

    Matzner , C. D., & McKee , C. F. 1999, , 510, 379, 10.1086/306571

    1999 doi

  52. [60]

    McKee , C. F. 1974, , 188, 335, 10.1086/152721

    1974 doi

  53. [61]

    F., & Truelove , J

    McKee , C. F., & Truelove , J. K. 1995, , 256, 157, 10.1016/0370-1573(94)00106-D

    1995 doi

  54. [62]

    D., & R \"o ttgering , H

    Mellema , G., Kurk , J. D., & R \"o ttgering , H. J. A. 2002, , 395, L13, 10.1051/0004-6361:20021408

    2002 doi

  55. [63]

    R., Dwek , E., & Slavin , J

    Micelotta , E. R., Dwek , E., & Slavin , J. D. 2016, , 590, A65, 10.1051/0004-6361/201527350

    2016 doi

  56. [64]

    Milisavljevic , D., & Fesen , R. A. 2013, , 772, 134, 10.1088/0004-637X/772/2/134

    2013 doi

  57. [65]

    2015, Science, 347, 526, 10.1126/science.1261949

    ---. 2015, Science, 347, 526, 10.1126/science.1261949

    2015 doi

  58. [66]

    2024, , 965, L27, 10.3847/2041-8213/ad324b

    Milisavljevic , D., Temim , T., De Looze , I., et al. 2024, , 965, L27, 10.3847/2041-8213/ad324b

    2024 doi

  59. [67]

    1959, in URSI Symp

    Minkowski , R. 1959, in URSI Symp. 1: Paris Symposium on Radio Astronomy, ed. R. N. Bracewell , Vol. 9, 315

    1959

  60. [68]

    1964, Annual Review of Astronomy and Astrophysics, 2, 247, 10.1146/annurev.aa.02.090164.001335

    Minkowski , R. 1964, Annual Review of Astronomy and Astrophysics, 2, 247, 10.1146/annurev.aa.02.090164.001335

    1964

  61. [69]

    1966, , 209, 1339, 10.1038/2091339a0

    ---. 1966, , 209, 1339, 10.1038/2091339a0

    1966 doi

  62. [70]

    1968, Nonthermal Galactic Radio Sources , ed

    ---. 1968, Nonthermal Galactic Radio Sources , ed. B. M. Middlehurst & L. H. Aller , 623

    1968

  63. [71]

    Minkowski , R., & Aller , L. H. 1954, , 119, 232, 10.1086/145814

    1954 doi

  64. [72]

    A., Fesen , R

    Morse , J. A., Fesen , R. A., Chevalier , R. A., et al. 2004, , 614, 727, 10.1086/423709

    2004 doi

  65. [73]

    1991, , 251, 505

    Mueller , E., Fryxell , B., & Arnett , D. 1991, , 251, 505

    1991

  66. [74]

    Nagasawa , M., Nakamura , T., & Miyama , S. M. 1988, , 40, 691

    1988

  67. [75]

    D., Tucker , M

    Neumann , K. D., Tucker , M. A., Kochanek , C. S., Shappee , B. J., & Stanek , K. Z. 2024, arXiv e-prints, arXiv:2407.14584, 10.48550/arXiv.2407.14584

    2024 doi arXiv

  68. [76]

    L., & Bocchino , F

    Orlando , S., Miceli , M., Pumo , M. L., & Bocchino , F. 2016, , 822, 22, 10.3847/0004-637X/822/1/22

    2016 doi

  69. [77]

    T., et al

    Orlando , S., Wongwathanarat , A., Janka , H. T., et al. 2021, , 645, A66, 10.1051/0004-6361/202039335

    2021 doi

  70. [78]

    2022, , 666, A2, 10.1051/0004-6361/202243258

    ---. 2022, , 666, A2, 10.1051/0004-6361/202243258

    2022 doi

  71. [79]

    J., & Fesen , R

    Patnaude , D. J., & Fesen , R. A. 2009, , 697, 535, 10.1088/0004-637X/697/1/535

    2009 doi

  72. [80]

    2014, , 789, 138, 10.1088/0004-637X/789/2/138

    ---. 2014, , 789, 138, 10.1088/0004-637X/789/2/138

    2014 doi

  73. [81]

    M., Clampin , M., De Marchi , G., et al

    Pavlovsky , C. M., Clampin , M., De Marchi , G., et al. 2002, in American Astronomical Society Meeting Abstracts, Vol. 200, American Astronomical Society Meeting Abstracts \#200, 62.01

    2002

  74. [82]

    1971, , 170, 261, 10.1086/151209

    Peimbert , M. 1971, , 170, 261, 10.1086/151209

    1971 doi

  75. [83]

    1971, , 167, 223, 10.1086/151024

    Peimbert , M., & van den Bergh , S. 1971, , 167, 223, 10.1086/151024

    1971 doi

  76. [84]

    A., & Bobin , J

    Picquenot , A., Acero , F., Holland-Ashford , T., Lopez , L. A., & Bobin , J. 2021, , 646, A82, 10.1051/0004-6361/202039170

    2021 doi

  77. [85]

    M., Falle , S

    Pittard , J. M., Falle , S. A. E. G., Hartquist , T. W., & Dyson , J. E. 2009, , 394, 1351, 10.1111/j.1365-2966.2009.13759.x

    2009

  78. [86]

    M., & Parkin , E

    Pittard , J. M., & Parkin , E. R. 2016, , 457, 4470, 10.1093/mnras/stw025

    2016 doi

  79. [87]

    Y., Frank , A., & Mitran , S

    Poludnenko , A. Y., Frank , A., & Mitran , S. 2004 a , , 613, 387, 10.1086/422988

    2004 doi

  80. [88]

    Y., Dannenberg , K

    Poludnenko , A. Y., Dannenberg , K. K., Drake , R. P., et al. 2004 b , , 604, 213, 10.1086/381792

    2004 doi

  81. [89]

    C., Esquivel , A., Riera , A., & Vel \'a zquez , P

    Raga , A. C., Esquivel , A., Riera , A., & Vel \'a zquez , P. F. 2007, , 668, 310, 10.1086/521143

    2007 doi

  82. [90]

    Raymond , J. C. 2018, , 214, 28, 10.1007/s11214-017-0453-6

    2018 doi

  83. [91]

    C., Koo , B

    Raymond , J. C., Koo , B. C., Lee , Y. H., et al. 2018, , 866, 128, 10.3847/1538-4357/aadf93

    2018 doi

  84. [92]

    E., Hester , J

    Reed , J. E., Hester , J. J., Fabian , A. C., & Winkler , P. F. 1995, , 440, 706, 10.1086/175308

    1995 doi

  85. [93]

    L., Suntzeff , N

    Rest , A., Welch , D. L., Suntzeff , N. B., et al. 2008, , 681, L81, 10.1086/590427

    2008 doi

  86. [94]

    J., Sinnott , B., et al

    Rest , A., Foley , R. J., Sinnott , B., et al. 2011, , 732, 3, 10.1088/0004-637X/732/1/3

    2011 doi

  87. [95]

    Ryle , M., & Smith , F. G. 1948, , 162, 462, 10.1038/162462a0

    1948 doi

  88. [96]

    2024, , 974, 245, 10.3847/1538-4357/ad739f

    Sakai , Y., Yamada , S., Sato , T., Hayakawa , R., & Kominato , N. 2024, , 974, 245, 10.3847/1538-4357/ad739f

    2024 doi

  89. [97]

    2018, , 853, 46, 10.3847/1538-4357/aaa021

    Sato , T., Katsuda , S., Morii , M., et al. 2018, , 853, 46, 10.3847/1538-4357/aaa021

    2018 doi

  90. [98]

    M., Vink , J., Garc \' a-Segura , G., & Achterberg , A

    Schure , K. M., Vink , J., Garc \' a-Segura , G., & Achterberg , A. 2008, , 686, 399, 10.1086/591432

    2008 doi

  91. [99]

    Shklovskii , I. S. 1973, , 16, 749

    1973

  92. [100]

    W., Smith , B

    Silvia , D. W., Smith , B. D., & Shull , J. M. 2010, , 715, 1575, 10.1088/0004-637X/715/2/1575

    2010 doi

  93. [101]

    2012, , 748, 12, 10.1088/0004-637X/748/1/12

    ---. 2012, , 748, 12, 10.1088/0004-637X/748/1/12

    2012 doi

  94. [102]

    J., Grindlay , J

    Simcoe , R. J., Grindlay , J. E., Los , E. J., et al. 2006, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 6312, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, ed. A. G. Tescher , 631217, 10.1117/12.681365

    2006 doi

  95. [103]

    Smith , F. G. 1951, , 168, 555, 10.1038/168555a0

    1951 doi

  96. [104]

    Smith , J. D. T., Rudnick , L., Delaney , T., et al. 2009, , 693, 713, 10.1088/0004-637X/693/1/713

    2009 doi

  97. [105]

    2013, , 30, e028, 10.1017/pas.2013.003

    Soria , R., Balestrieri , R., & Ohtsuka , Y. 2013, , 30, e028, 10.1017/pas.2013.003

    2013 doi

  98. [106]

    R., Fesen , R

    Thorstensen , J. R., Fesen , R. A., & van den Bergh , S. 2001, , 122, 297, 10.1086/321138

    2001 doi

  99. [107]

    K., & McKee , C

    Truelove , J. K., & McKee , C. F. 1999, , 120, 299, 10.1086/313176

    1999 doi

  100. [108]

    1971 a , , 165, 259, 10.1086/150895

    van den Bergh , S. 1971 a , , 165, 259, 10.1086/150895

    1971 doi

  101. [109]

    1971 b , , 165, 457, 10.1086/150913

    ---. 1971 b , , 165, 457, 10.1086/150913

    1971 doi

  102. [110]

    1971 c , in IAU Symposium, Vol

    van den Bergh , S. 1971 c , in IAU Symposium, Vol. 46, The Crab Nebula, ed. R. D. Davies & F. Graham-Smith , 263

    1971

  103. [111]

    1974, in The Outer Layers of Novae and Supernovae, 559--563

    van den Bergh , S. 1974, in The Outer Layers of Novae and Supernovae, 559--563

    1974

  104. [112]

    van den Bergh , S., & Dodd , W. W. 1970, , 162, 485, 10.1086/150681

    1970 doi

  105. [113]

    1985, , 293, 537, 10.1086/163259

    van den Bergh , S., & Kamper , K. 1985, , 293, 537, 10.1086/163259

    1985 doi

  106. [114]

    van den Bergh , S., & Kamper , K. W. 1983, , 268, 129, 10.1086/160938

    1983 doi

  107. [115]

    van den Bergh , S., & Pritchet , C. J. 1986, , 307, 723, 10.1086/164457

    1986 doi

  108. [116]

    S., & Bleeker , J

    Vink , J., Bloemen , H., Kaastra , J. S., & Bleeker , J. A. M. 1998, , 339, 201. astro-ph/9806319

    1998 arXiv

  109. [117]

    J., & Castro , D

    Vink , J., Patnaude , D. J., & Castro , D. 2022, , 929, 57, 10.3847/1538-4357/ac590f

    2022 doi

  110. [118]

    Wang , C.-Y., & Chevalier , R. A. 2001, , 549, 1119, 10.1086/319439

    2001 doi

  111. [119]

    E., Fesen , R

    Weil , K. E., Fesen , R. A., Patnaude , D. J., et al. 2020, , 891, 116, 10.3847/1538-4357/ab76bf

    2020 doi

  112. [120]

    C., Maund , J

    Wheeler , J. C., Maund , J. R., & Couch , S. M. 2008, , 677, 1091, 10.1086/528366

    2008 doi

  113. [121]

    Willingale , R., Bleeker , J. A. M., van der Heyden , K. J., Kaastra , J. S., & Vink , J. 2002, , 381, 1039, 10.1051/0004-6361:20011614

    2002 doi

  114. [122]

    2017, , 842, 13, 10.3847/1538-4357/aa72de

    Wongwathanarat , A., Janka , H.-T., M \"u ller , E., Pllumbi , E., & Wanajo , S. 2017, , 842, 13, 10.3847/1538-4357/aa72de

    2017 doi

  115. [123]

    Wu , Y., & Yang , X. J. 2024, , 969, 155, 10.3847/1538-4357/ad509f

    2024 doi

  116. [124]

    2020, Research in Astronomy and Astrophysics, 20, 048, 10.1088/1674-4527/20/4/48

    Yang , C.-Y., Bao , B.-W., & Liu , S.-M. 2020, Research in Astronomy and Astrophysics, 20, 048, 10.1088/1674-4527/20/4/48

    2020 doi

  117. [125]

    A., Fryer , C

    Young , P. A., Fryer , C. L., Hungerford , A., et al. 2006, , 640, 891, 10.1086/500108

    2006 doi

  118. [126]

    2010, , 139, 2184, 10.1088/0004-6256/139/6/2184

    Zacharias , N., Finch , C., Girard , T., et al. 2010, , 139, 2184, 10.1088/0004-6256/139/6/2184

    2010 doi

Pith tools

Reviewed August 10, 2026 · model on record in the stance chip above.