Pith. sign in

REVIEW 3 major objections 3 minor 100 references

The Quasar-associated 2175 \AA\ Dust Absorbers in the SDSS DR16 Quasar Catalog

T0 review · 3 major / 3 minor · reviewed 2026-08-07 · deepseek-v4-flash

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

Pith's one-line read The paper claims that 843 quasar-associated 2175 Å dust absorbers show a statistically significant decline in bump strength with redshift, which would imply dust evolution in quasar environments.

desk verdict Valuable catalog, real sample, but the two headline claims—weak bump strengths and the redshift decline—need normalization and bias corrections before they can be believed. read the letter →

arxiv 2505.20706 v1 pith:JI2WTYCY submitted 2025-05-27 astro-ph.GA

Shaohua Zhang , Yuchong Luo , Shangchun Xie , Chao Gao , Zhijian Luo , Chenggang Shu , Hubing Xiao This is my paper · ORCID
classification astro-ph.GA
keywords 2175Ådustabsorbersquasar-associatedinterstellarextinctionDrudeprofileevolutionbroadabsorptionlinequasarsSDSSDR16LargeMagellanicCloud
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 reports the first systematic search for 2175 Å dust absorbers that share a quasar's own redshift, using SDSS DR16 spectra and photometry for 557,674 quasars. The authors claim to have found 843 such absorbers at high confidence, nearly 50 times the previously known sample of quasar-associated or intrinsic bumps, and they find that the bump strength falls as redshift rises. The central physical claim is that dust in quasar environments changes between z ~ 0.7 and z ~ 2.4: on average the absorbers are weak and narrow, closer to the Large Magellanic Cloud than to the Milky Way, and more than a third of the hosts are broad absorption line quasars. If the trend is real, quasar environments offer a direct, large sample for tracking how interstellar dust grains are built or destroyed over cosmic time.

What carries the argument

The argument runs on a parametric extinction-curve fit in inverse wavelength $x=\lambda^{-1}$, following a standard Fitzpatrick–Massa form $A(\lambda)=c_1+c_2x+c_3D(x,x_0,\gamma)$, where the 2175 Å feature is modelled by a Drude profile $D(x,x_0,\gamma)=x^2/((x^2-x_0^2)^2+x^2\gamma^2)$ with peak position $x_0$, width $\gamma$, and bump strength $A_{\rm bump}=\pi c_3/2\gamma$. The observed spectrum is compared with a fixed quasar composite (optical composite plus near-infrared extension), so the derived extinction and $A_{\rm bump}$ are unnormalized. A three-stage least-squares procedure fits the linear extinction first, then the bump parameters, then rejects $>3\sigma$ outliers and refits; because continuum features like broad Fe II emission can mimic a bump, each candidate is tested against control quasar spectra at similar redshift and only $>3\sigma$ detections are kept. The key comparison that carries the redshift-evolution claim is the distribution of the fitted $A_{\rm bump}$ against quasar redshift, with completeness caveats at low redshift and near $z\sim1.7$ documented in the same section.

What would settle it

Recover the bump strength from simulated quasar spectra that have a known Drude bump injected and then run them through the same pipeline at many redshifts; if the recovery of $A_{\rm bump}$ varies with redshift, the claimed trend is an artifact. A simpler check is to recompute the Spearman correlation using only absorbers whose rest-frame coverage brackets the entire bump on both sides; if the null probability rises above $10^{-3}$, the evolutionary claim would not survive.

Watch

Extended reading notes

Core claim

The paper's central discovery is that quasar-associated 2175 Å dust absorbers are common enough to be studied statistically, and their fitted Drude-bump parameters evolve with redshift. From 843 absorbers in the range $0.7\le z\le2.4$, the authors derive mean bump strength $A_{\rm bump}=0.49\pm0.15\,\mu m^{-1}$ and width $\gamma=0.81\pm0.14\,\mu m^{-1}$, with peak positions $\lambda^{-1}=x_0$ spread from 4.2 to $4.84\,\mu m^{-1}$; the average extinction curve is LMC-like but shallower. A Spearman correlation between bump strength and redshift has null probability $Pr\sim10^{-10}$, and the binned trend has slope $-0.13$, which the paper interprets as grains growing or otherwise changing in quasar environments at later cosmic epochs. The paper also finds that over one third of the absorbers reside in BAL quasars, and that in those systems the bump peaks at systematically lower $x_0$, a shift it attributes to environmental differences in dust grain properties.

Load-bearing premise

The whole redshift-evolution result depends on the assumption that the measured bump strength means the same thing at every redshift, even though the observed wavelength window and the quasar selection both change sharply across the sample's redshift range.

Editorial extensions

If this is right

  • With 843 confirmed absorbers, quasar-associated 2175 Å dust can be compared across redshift bins, something the roughly 18 earlier detections could not support.
  • If the $A_{\rm bump}$–$z$ correlation is unbiased, dust in quasar environments was systematically different at $z\sim2.4$ than at $z\sim0.7$, meaning quasar hosts participate in dust evolution rather than always destroying the bump carriers.
  • The excess of BAL quasars among the absorbers (more than a third, versus typical optically selected fractions) connects the 2175 Å feature to outflow activity, with BAL bumps peaking at lower $x_0$.
  • The average LMC-like but shallower extinction curves provide a local benchmark for dust models of quasar environments and imply the strong Milky Way-type bump is not typical there.

Reading between the lines

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

  • Editorial inference: the redshift trend could be tested against selection effects by computing the recovery fraction of injected synthetic bumps as a function of $z$; if recovery declines at high $z$, part of the $Pr\sim10^{-10}$ signal would be an artifact.
  • Editorial inference: because the paper's own completeness notes show fewer detections at $z<1.2$ and a dip near $z\sim1.7$, combining the quasar-associated sample with the authors' forthcoming intervening-absorber sample would provide an independent check of whether bump strength genuinely rises toward the local universe.
  • Editorial inference: a photometry-only search for reddened quasars missed by SDSS target selection could test whether the absence of very strong bumps in quasar-associated absorbers is physical or a selection effect, since heavily reddened quasars are underrepresented.
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

3 major / 3 minor

Summary. The paper presents a systematic search for 2175 \AA absorption bumps in the spectra of 557,674 SDSS DR16 quasars at 0.7 \leq z \leq 2.4. The analysis fits each quasar with a reddened composite plus a Drude profile, applies a 3\sigma significance test against control spectra, and reports 843 quasar-associated absorbers. The paper reports mean bump strength Abump = 0.49 \pm 0.15 \um^-1, width gamma = 0.81 \pm 0.14 \um^-1, peak positions x0 = 4.2 to 4.84 \um^-1, an over-representation of BAL quasars, BAL-dependent peak shifts, and a statistically significant negative correlation between Abump and redshift (Spearman Pr \approx 10^-10), interpreted as dust evolution.

Significance. If robust, the catalog is a major enlargement (roughly 50x) of known quasar-associated 2175 Angstrom absorbers and would provide a homogeneous sample for studying dust in quasar environments. The paper uses an established pair/composite method, a control-sample significance estimator, explicit masking of strong lines, and it recovers 12 of 18 previously known absorbers, which are notable strengths. However, the headline quantitative claims, namely weak bump strength relative to the Milky Way and the redshift evolution of Abump, currently rest on unnormalized measurements and on completeness/coverage effects that the authors acknowledge but do not quantitatively correct. The significance of the scientific conclusions is therefore lower than presented.

major comments (3)
  1. [Section 4, Figure 6 (with Figure 2)] The claim of a redshift evolution of bump strength is not supported by the presented analysis because the measurement is not corrected for the strong redshift dependence of rest-frame wavelength coverage and detection completeness. At z \approx 0.7 the BOSS window covers only to x \approx 4.78 \um^-1 on the blue side of the 2175 Angstrom feature, while at z \approx 2.4 it reaches x \approx 9.55 \um^-1; a Drude profile with a truncated blue wing is degenerate with the linear slope c2 and biases the fitted c3, x0, and gamma. The authors themselves document a detection-rate deficit at z < 1.2 and a dip at z \approx 1.7 (Figure 2), and no completeness or bias correction is applied to the binned means and Spearman test in Figure 6. Because detection probability at fixed true Abump is expected to increase with redshift as more of the bump becomes covered, the observed negative slope (and its Pr \approx 10^-10) can arise as a selection artifact. An injection-recovery calibration using synthetic bumps embedded in real quasar spectra is required before the evolutionary interpretation can be accepted.
  2. [Section 3 and Section 4] The comparison of the measured mean Abump = 0.49 \pm 0.15 \um^-1 with the Milky Way value Abump = 2.48 \pm 1.15 \um^-1 is not well posed. In Section 3 the authors correctly state that their Abump is an unnormalized relative quantity, whereas the Fitzpatrick & Massa (2007) and Gordon et al. (2003) values are normalized to E(B-V) or to a conventional extinction curve. With no normalization or stated relative-to-continuum definition, the abstract and summary statements that these absorbers exhibit weak bump strengths and that the curves resemble an LMC-like but shallower extinction curve do not follow from the data. The authors should either define an appropriate normalization or rephrase the claim as a relative comparison between quasar-associated absorbers at different redshifts, not as an absolute comparison with Local Group measurements.
  3. [Section 4, Figure 5] The reported peak-position difference between BAL and non-BAL quasars is confounded by the hard lower boundary x0 = 4.2 \um^-1 imposed in fitting. The authors note that a substantial fraction of the sample clusters at x0 = 4.2 to 4.36 \um^-1 and that this clustering may not fully reflect the true distribution; because the BAL subsample is preferentially found at low x0, the comparison in Figure 5 is affected by the same truncation. The physical interpretation of larger PAH molecules in BAL quasars is therefore premature until the x0 boundary and its effect on the BAL/non-BAL comparison are modeled or otherwise accounted for.
minor comments (3)
  1. [Section 3] Please state the exact parameter bounds and priors for x0 and gamma, including the x0 = 4.2 lower limit mentioned only in Section 4, and provide the full masking list, so that the fitting procedure can be reproduced from the text.
  2. [Abstract and Table 1] The units reported for Abump appear to be inconsistent: since Abump is defined as the integral of c3 times the Drude profile over x, the natural units are mag \um^-1 rather than \um^-1 as written in the abstract and table.
  3. [Figure 6] Please report the Spearman rank correlation coefficient and the uncertainty on the fitted slope, rather than only the null probability; the four binned means with a slope of -0.13 are not presented as a formal fit and their uncertainties are not given.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the paper is an empirical template-fit catalog, and its central claims are measured correlations rather than derivations that reduce to their inputs.

full rationale

The derivation chain is: composite spectra (Vanden Berk 2001; Glikman 2006) are reddened by the Fitzpatrick-Massa parameterization; each quasar spectrum is fit with linear plus Drude terms; candidates are screened by a control-sample 3-sigma significance test; fitted bump parameters are then summarized and correlated with redshift. Each stage is a measurement, not a derivation. The 3-sigma threshold is supported by a self-cited prior simulation study (Zhang et al. 2015), but that study is an externally published, independent simulation not fitted to this sample, so it is real evidence rather than a circular load. The paper explicitly records its measurement limitations (x0=4.2 fit boundary, low detection rate at z<1.2, the dip near z~1.7, and SDSS selection against red quasars), and the unnormalized Abump is not comparable to normalized MW values; these are validity and comparability concerns, not circular reductions. No equation or fitted parameter in the paper is equivalent by construction to the claimed output, so the paper is not circular in the sense defined here.

Assumptions & free parameters 6 free parameters · 6 assumptions · 0 invented entities

The paper's contribution is a catalog of 843 fitted bump systems; every physical conclusion depends on the composite-template decomposition, on Drude parameters fitted per quasar, and on a rejection threshold validated in the authors' own prior simulation work. There are six groups of fitted parameters per source and six domain assumptions, but no invented entities. The honesty of the catalog therefore rests on the control-sample statistics and visual inspection rather than on independent external calibration of bump strength.

free parameters (6)
  • c1, intercept of the relative extinction curve = per quasar, e.g., 7.19 to 9.47 mag in Table 1
    Absorbs the flux normalization mismatch between the fixed composite template and each quasar; sets the arbitrary vertical scale of A(lambda).
  • c2, linear slope of the relative extinction curve = per quasar, e.g., -0.17 to +0.37 um in Table 1
    Absorbs intrinsic spectral slope differences between the quasar and the composite; can be negative for quasars bluer than the composite.
  • c3, Drude bump amplitude = per quasar, 0.14 to 0.40 mag in Table 1 excerpts
    The central fitted quantity; Abump = pi*c3/(2*gamma). The paper's 'weak bump strengths' and the redshift trend are claims about this fitted amplitude.
  • x0, Drude peak position = fitted within 4.20 to 4.84 um^-1
    Fitted with a lower bound of 4.2 um^-1; a substantial fraction of sources cluster at the boundary, which the authors say may not reflect the true distribution.
  • gamma, Drude width = fitted within about 0.54 to 0.99 um^-1
    Restricted to the range spanned by Galactic and LMC curve parameters during fitting.
  • per-quasar photometric recalibration polynomial = three coefficients per quasar from a second-order polynomial
    Applied to bring SDSS spectral fluxes into agreement with griz photometry before extinction fitting.
assumptions (6)
  • domain assumption The Vanden Berk et al. (2001) optical plus Glikman et al. (2006) NIR composite is an adequate unreddened template for every quasar up to a linear correction c1+c2x.
    Section 3: the extinction curve is defined as -2.5log(f_obs/f_model) with the composite as f_model. Residual intrinsic SED differences, if bump-shaped (for example Fe II emission), can masquerade as a 2175 A bump.
  • domain assumption Residuals that survive the linear correction and resemble a Drude profile are dust extinction rather than Fe II or other line artifacts.
    Section 3: nearly 40% of quasars show positive c3 before rejection, and the control-sample simulation is used to remove Fe II mimics. The validation that almost all simulated false bumps fall below 3 sigma is cited from the authors' own Zhang et al. (2015), not reproduced here.
  • domain assumption The DR16Q catalog redshifts are correct and correspond to the dust location.
    Section 3: the bump is fixed to the quasar redshift during fitting; a wrong redshift would distort x0 and gamma and could create or destroy apparent bumps.
  • domain assumption The Fitzpatrick and Massa (2007) parametric form, with the FUV c4 term dropped, describes quasar extinction over the observed window.
    Section 3: the c4 term is excluded as unconstrained. The fit is anchored redward of the bump, where composite-quasar mismatch may not be fully captured by a straight line.
  • domain assumption Control quasars have the same intrinsic SED distribution as absorber quasars, so subtracting control-sample average curves yields an unbiased average extinction curve.
    Section 4, bottom panels of Figure 4: if absorber quasars are intrinsically redder than the controls, the 'shallower than LMC' slope conclusion would be biased.
  • standard math The Schlegel et al. (1998) dust map with the Fitzpatrick (1999) reddening curve correctly removes Galactic foreground extinction.
    Section 3, dereddening step; this is standard practice in the field.

how reviews work

0 comments
Cite this review

Pith. "Pith review of The Quasar-associated 2175 \AA\ Dust Absorbers in the SDSS DR16 Quasar Catalog." pith.science (2026). https://pith.science/paper/JI2WTYCY

@misc{pith2026250520706,
  author       = {Pith},
  title        = {Pith review of: The Quasar-associated 2175 \AA\ Dust Absorbers in the SDSS DR16 Quasar Catalog},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/JI2WTYCY}},
  note         = {Machine review of arXiv:2505.20706}
}
abstract

We present, for the first time, a systematic study of quasar-associated 2175 \AA\ dust absorbers using spectroscopic data from the Sloan Digital Sky Survey (SDSS) Data Release 16 (DR16). By analyzing the optical spectra and multi-band magnitudes of 557,674 quasars in the redshift range of $0.7 \le z \le 2.4$, we identify 843 absorbers that share the same redshifts as quasars and are believed to originate from dust in the quasar nuclei, the host galaxies, or their surrounding environments. These absorbers exhibit weak bump strengths ($A\rm_{bump}=0.49\pm0.15~\mu m^{-1}$) and narrow widths ($\gamma\rm=0.81\pm0.14~\mu m^{-1}$), while their peak positions span a broad range from $x_0 = 4.2$ to $4.84~ \mu m^{-1}$. Their average extinction curves resemble those of the Large Magellanic Cloud (LMC) but exhibit a shallower slope. In broad absorption line (BAL) quasars, the absorption bumps show systematic shifts in peak positions. Although further confirmation is needed, this may suggest environmental differences in dust grain properties. We find a statistically significant negative correlation between bump strength and redshift, suggesting possible evolution in dust properties. These findings highlight the changing composition and physical conditions of dust in quasar environments, likely influenced by factors such as metallicity, radiation fields, and dust processing mechanisms. Future studies incorporating ultraviolet and infrared data will be essential for refining the dust evolution models. Machine learning techniques and high-resolution spectroscopic follow-ups could enhance sample completeness and provide deeper insights into the chemical properties of the dust absorbers.

Figures

Figures reproduced from arXiv: 2505.20706 by the authors.

Figure 1
Figure 1. Best-fit extinction models of eight quasars for examples. In each panel, the quasar spectra, including both the original SDSS spectrum (gray curve) and the recalibrated spectrum (black curve), are overlaid for comparison. Multi-band magnitudes from GALEX, SDSS, 2MASS, UKIDSS, and WISE are marked with orange squares, while synthetic magnitudes at g, r, i, and z bands, derived from the convolution of the original spec… view at source ↗
Figure 2
Figure 2. Redshift distribution of quasar-associated 2175 ˚A dust absorbers (black curve), with that of DR16Q quasars (grey curve) overplotted for comparison. this work, for each bump candidate, we selected con￾trol quasar spectra with an i ′−band signal-to-noise ra￾tio of S/N ≥ 6 and emission redshifts within the range zem − 0.05 < z < zem + 0.05, where zem is the emission redshift of the quasar from the DR16 database. Only … view at source ↗
Figure 3
Figure 3. Best-fit extinction models for two rejected candidates reported by Jiang et al. (2011). The annotations are the same as those in [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figures from the paper (3 more)
Figure 4
Figure 4. Figure 4: Top: Comparison of bump parameters with 2175 ˚A bumps in MW (blue circles), LMC average (cyan circles), LMC2 Supershell (green circles) and SMC (navy circles). The quasar-associated 2175 ˚A dust absorbers are labeled with black points. Bottom: Colored plots display the…
Figure 5
Figure 5. Figure 5: Comparison of bump parameter distributions (top panels) and composite spectra (bottom panels) of quasars with and without BALs and NALs. sitions. A possible explanation is that the average dust grain size responsible for 2175 ˚A dust absorbers differs between these two…
Figure 6
Figure 6. Figure 6: Redshift vs. 2175 ˚A bump strength for different dust absorber populations. Quasar-associated 2175 ˚A dust absorbers are represented by black points. Blue circles indicate dust bumps observed in the MW, navy circles denote bumps in the SMC, while cyan and green circles…

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

100 extracted references · 31 canonical work pages

  1. [1]

    doi:10.1088/0004-637X/736/2/82

    Alonso-Herrero, A., Ramos Almeida, C., Mason, R., et al.\ 2011, , 736, 82. doi:10.1088/0004-637X/736/2/82

    doi:10.1088/0004-637x/736/2/82 2011

  2. [2]

    doi:10.1093/mnras/stab871

    Anand, A., Nelson, D., & Kauffmann, G.\ 2021, , 504, 65. doi:10.1093/mnras/stab871

    doi:10.1093/mnras/stab871 2021

  3. [3]

    doi:10.1146/annurev.aa.31.090193.002353

    Antonucci, R.\ 1993, , 31, 473. doi:10.1146/annurev.aa.31.090193.002353

    arXiv 1993

  4. [4]

    doi:10.1086/165571

    Barvainis, R.\ 1987, , 320, 537. doi:10.1086/165571

    doi:10.1086/165571 1987

  5. [5]

    L., & Gry, C.\ 1994, , 284, 956

    Boulanger, F., Prevot, M. L., & Gry, C.\ 1994, , 284, 956

    1994

  6. [6]

    & Temi, P.\ 2005, , 621, 831

    Bregman, J. & Temi, P.\ 2005, , 621, 831. doi:10.1086/427738

    work page doi:10.1086/427738 2005

  7. [7]

    doi:10.1051/0004-6361/201219405

    Buat, V., Noll, S., Burgarella, D., et al.\ 2012, , 545, A141. doi:10.1051/0004-6361/201219405

    doi:10.1051/0004-6361/201219405 2012

  8. [8]

    Bless, R. C. & Savage, B. D.\ 1970, Ultraviolet Stellar Spectra and Related Ground-Based Observations, 36, 28

    1970

Show all 100 references
  1. [9]

    L., & Storchi-Bergmann, T.\ 1994, , 429, 582

    Calzetti, D., Kinney, A. L., & Storchi-Bergmann, T.\ 1994, , 429, 582. doi:10.1086/174346

    1994 doi

  2. [10]

    doi:10.1093/mnras/stac308

    Cappellazzo, E., Zafar, T., Corcho-Caballero, P., et al.\ 2022, , 517, 6022. doi:10.1093/mnras/stac308

    2022 doi

  3. [11]

    A., Clayton, G

    Cardelli, J. A., Clayton, G. C., & Mathis, J. S.\ 1989, , 345, 245. doi:10.1086/167900

    1989 doi

  4. [12]

    doi:10.1051/0004-6361/202244806

    Garc \' a-Bernete, I., Rigopoulou, D., Alonso-Herrero, A., et al.\ 2022, , 666, L5. doi:10.1051/0004-6361/202244806

    2022 doi

  5. [13]

    R., et al.\ 2024, , 691, A162

    Garc \' a-Bernete, I., Rigopoulou, D., Donnan, F. R., et al.\ 2024, , 691, A162. doi:10.1051/0004-6361/202450086

    2024 doi

  6. [14]

    M., Kraemer, S

    Crenshaw, D. M., Kraemer, S. B., Bruhweiler, F. C., et al.\ 2001, , 555, 633. doi:10.1086/321522

    2001 doi

  7. [15]

    doi:10.1051/0004-6361:20035741

    Czerny, B., R \'o \.z a \'n ska, A., Dov c iak, M., et al.\ 2004, , 420, 1. doi:10.1051/0004-6361:20035741

    2004 doi

  8. [16]

    S., Kneib, J.-P., Percival, W

    Dawson, K. S., Kneib, J.-P., Percival, W. J., et al.\ 2016, , 151, 44. doi:10.3847/0004-6256/151/2/44

    2016 doi

  9. [17]

    T.\ 1989, Infrared Spectroscopy in Astronomy, 93

    Draine, B. T.\ 1989, Infrared Spectroscopy in Astronomy, 93

    1989

  10. [18]

    T.\ 2003, , 41, 241

    Draine, B. T.\ 2003, , 41, 241. doi:10.1146/annurev.astro.41.011802.094840

    2003 arXiv

  11. [19]

    El \' asd \'o ttir, \'A ., Fynbo, J. P. U., Hjorth, J., et al.\ 2009, , 697, 1725. doi:10.1088/0004-637X/697/2/1725

    2009 doi

  12. [21]

    doi:10.3847/1538-4357/aabcbc

    Esparza-Arredondo, D., Gonz \'a lez-Mart \' n, O., Dultzin, D., et al.\ 2018, , 859, 124. doi:10.3847/1538-4357/aabcbc

    2018 doi

  13. [22]

    doi:10.1093/mnras/stac3473

    Fang, H., Xia, I., Ge, J., et al.\ 2023, , 518, 5590. doi:10.1093/mnras/stac3473

    2023 doi

  14. [23]

    doi:10.1088/0004-637X/717/2/868

    Farrah, D., Urrutia, T., Lacy, M., et al.\ 2010, , 717, 868. doi:10.1088/0004-637X/717/2/868

    2010 doi

  15. [24]

    L.\ 1999, , 111, 63

    Fitzpatrick, E. L.\ 1999, , 111, 63. doi:10.1086/316293

    1999 doi

  16. [25]

    L., & Massa, D.\ 1986, , 307, 286

    Fitzpatrick, E. L., & Massa, D.\ 1986, , 307, 286. doi:10.1086/164415

    1986 doi

  17. [26]

    Fitzpatrick, E. L. & Massa, D.\ 2007, , 663, 320. doi:10.1086/518158

    2007 doi

  18. [27]

    M., Goosmann, R

    Gaskell, C. M., Goosmann, R. W., Antonucci, R. R. J., et al.\ 2004, , 616, 147. doi:10.1086/423885

    2004 doi

  19. [28]

    Gaskell, C. M. & Benker, A. J.\ 2007, arXiv:0711.1013. doi:10.48550/arXiv.0711.1013

    2007 doi arXiv

  20. [29]

    doi:10.1093/mnras/stae799

    Ge, J., Willis, K., Chao, K., et al.\ 2024, , 531, 387. doi:10.1093/mnras/stae799

    2024 doi

  21. [30]

    R., Jiang, L., Brandt, W

    Gibson, R. R., Jiang, L., Brandt, W. N., et al.\ 2009, , 692, 758. doi:10.1088/0004-637X/692/1/758

    2009 doi

  22. [31]

    doi:10.1051/0004-6361/202449659

    Greiner, J., Kr \"u hler, T., Bolmer, J., et al.\ 2024, , 691, A158. doi:10.1051/0004-6361/202449659

    2024 doi

  23. [32]

    J., & White, R

    Glikman, E., Helfand, D. J., & White, R. L.\ 2006, , 640, 579. doi:10.1086/500098

    2006 doi

  24. [33]

    D., & Clayton, G

    Gordon, K. D., & Clayton, G. C.\ 1998, , 500, 816. doi: 10.1086/305774

    1998 doi

  25. [34]

    D., Clayton, G

    Gordon, K. D., Clayton, G. C., Misselt, K. A., et al.\ 2003, , 594, 279. doi:10.1086/376774

    2003 doi

  26. [35]

    D., Fitzpatrick, E

    Gordon, K. D., Fitzpatrick, E. L., Massa, D., et al.\ 2024, , 970, 51. doi:10.3847/1538-4357/ad4be1

    2024 doi

  27. [36]

    Hao, L., Spoon, H. W. W., Sloan, G. C., et al.\ 2005, , 625, L75. doi:10.1086/431227

    2005 doi

  28. [37]

    E., Zafar, T., De Cia, A., et al.\ 2019, , 486, 2063

    Heintz, K. E., Zafar, T., De Cia, A., et al.\ 2019, , 486, 2063. doi:10.1093/mnras/stz1012

    2019 doi

  29. [38]

    doi:10.1093/mnras/stac3394

    Hirashita, H.\ 2023, , 518, 3827. doi:10.1093/mnras/stac3394

    2023 doi

  30. [39]

    F., Strauss, M

    Hopkins, P. F., Strauss, M. A., Hall, P. B., et al.\ 2004, , 128, 1112. doi:10.1086/423291

    2004 doi

  31. [40]

    J., H \"o nig, S

    Jensen, J. J., H \"o nig, S. F., Rakshit, S., et al.\ 2017, , 470, 3071. doi:10.1093/mnras/stx1447

    2017 doi

  32. [41]

    X., et al.\ 2010a, , 720, 328

    Jiang, P., Ge, J., Prochaska, J. X., et al.\ 2010a, , 720, 328. doi:10.1088/0004-637X/720/1/328

    doi

  33. [42]

    X., et al.\ 2010b, , 724, 1325

    Jiang, P., Ge, J., Prochaska, J. X., et al.\ 2010b, , 724, 1325. doi:10.1088/0004-637X/724/2/1325

    doi

  34. [43]

    doi:10.1088/0004-637X/732/2/110

    Jiang, P., Ge, J., Zhou, H., et al.\ 2011, , 732, 110. doi:10.1088/0004-637X/732/2/110

    2011 doi

  35. [44]

    T., Cohen, R

    Junkkarinen, V. T., Cohen, R. D., Beaver, E. A., et al.\ 2004, , 614, 658. doi:10.1086/423777

    2004 doi

  36. [45]

    & Conroy, C.\ 2013, , 775, L16

    Kriek, M. & Conroy, C.\ 2013, , 775, L16. doi:10.1088/2041-8205/775/1/L16

    2013 doi

  37. [46]

    J., Almaini, O., et al.\ 2007, , 379, 1599

    Lawrence, A., Warren, S. J., Almaini, O., et al.\ 2007, , 379, 1599. doi:10.1111/j.1365-2966.2007.12040.x

    2007

  38. [47]

    J., & Li, A.\ 2023, , 525, 2380

    Lin, Q., Yang, X. J., & Li, A.\ 2023, , 525, 2380. doi:10.1093/mnras/stad2405

    2023 doi

  39. [48]

    T.\ 2001, , 554, 778

    Li, A., & Draine, B. T.\ 2001, , 554, 778. doi:10.1086/323147

    2001 doi

  40. [49]

    doi:10.1051/0004-6361/201424122

    Ledoux, C., Noterdaeme, P., Petitjean, P., et al.\ 2015, , 580, A8. doi:10.1051/0004-6361/201424122

    2015 doi

  41. [50]

    Liang, S. L. & Li, A.\ 2010, , 710, 648. doi:10.1088/0004-637X/710/1/648

    2010 doi

  42. [51]

    J., et al.\ 2007, , 661, L25

    Lutz, D., Sturm, E., Tacconi, L. J., et al.\ 2007, , 661, L25. doi:10.1086/518537

    2007 doi

  43. [52]

    W., Higley, A

    Lyke, B. W., Higley, A. N., McLane, J. N., et al.\ 2020, , 250, 8. doi:10.3847/1538-4365/aba623

    2020 doi

  44. [53]

    doi:10.1093/mnras/stv2073

    Ma, J., Caucal, P., Noterdaeme, P., et al.\ 2015, , 454, 1751. doi:10.1093/mnras/stv2073

    2015 doi

  45. [54]

    doi:10.1093/mnras/stx2117

    Ma, J., Ge, J., Zhao, Y., et al.\ 2017, , 472, 2196. doi:10.1093/mnras/stx2117

    2017 doi

  46. [55]

    doi:10.3847/2041-8213/aabc51

    Ma, J., Brammer, G., Ge, J., et al.\ 2018, , 857, L12. doi:10.3847/2041-8213/aabc51

    2018 doi

  47. [56]

    doi:10.1093/mnras/staa2061

    Ma, X.-Y., Zhu, Y.-Y., Yan, Q.-B., et al.\ 2020, , 497, 2190. doi:10.1093/mnras/staa2061

    2020 doi

  48. [57]

    10.1051/0004-6361:20000177

    Maiolino, R., Marconi, A., & Oliva, E.\ 2001, , 365, 28. 10.1051/0004-6361:20000177

    2001 doi

  49. [58]

    C., Fanson, J., Schiminovich, D., et al.\ 2005, , 619, L1

    Martin, D. C., Fanson, J., Schiminovich, D., et al.\ 2005, , 619, L1. doi:10.1086/426387

    2005 doi

  50. [59]

    D., & Fitzpatrick, E

    Massa, D., Gordon, K. D., & Fitzpatrick, E. L.\ 2022, , 925, 19. doi:10.3847/1538-4357/ac3825

    2022 doi

  51. [60]

    A., et al.\ 2002, , 574, 719

    Motta, V., Mediavilla, E., Mu \ n oz, J. A., et al.\ 2002, , 574, 719. doi:10.1086/341118

    2002 doi

  52. [61]

    M., Nikutta, R., et al.\ 2008, , 685, 160

    Nenkova, M., Sirocky, M. M., Nikutta, R., et al.\ 2008, , 685, 160. doi:10.1086/590483

    2008 doi

  53. [62]

    doi:10.1146/annurev-astro-082214-122302

    Netzer, H.\ 2015, , 53, 365. doi:10.1146/annurev-astro-082214-122302

    2015 doi

  54. [63]

    doi:10.1051/0004-6361:20077067

    Noll, S., Pierini, D., Pannella, M., et al.\ 2007, , 472, 455. doi:10.1051/0004-6361:20077067

    2007 doi

  55. [64]

    doi:10.1051/0004-6361/200912330

    Noterdaeme, P., Ledoux, C., Srianand, R., et al.\ 2009, , 503, 765. doi:10.1051/0004-6361/200912330

    2009 doi

  56. [65]

    doi:10.3847/1538-4357/835/2/218

    Pan, X., Zhou, H., Ge, J., et al.\ 2017, , 835, 218. doi:10.3847/1538-4357/835/2/218

    2017 doi

  57. [66]

    M., Clayton, G

    Pitman, K. M., Clayton, G. C., & Gordon, K. D.\ 2000, , 112, 537. doi:10.1086/316551

    2000 doi

  58. [67]

    X., Worseck, G., & O'Meara, J

    Prochaska, J. X., Worseck, G., & O'Meara, J. M.\ 2009, , 705, L113. doi: 10.1088/0004-637X/705/2/L113

    2009 doi

  59. [68]

    X., Sheffer, Y., Perley, D

    Prochaska, J. X., Sheffer, Y., Perley, D. A., et al.\ 2009, , 691, L27. doi:10.1088/0004-637X/691/1/L27

    2009 doi

  60. [69]

    T., Fan, X., Newberg, H

    Richards, G. T., Fan, X., Newberg, H. J., et al.\ 2002, , 123, 2945. doi:10.1086/340187

    2002 doi

  61. [70]

    T., Hall, P

    Richards, G. T., Hall, P. B., Vanden Berk, D. E., et al.\ 2003, , 126, 1131. doi:10.1086/377014

    2003 doi

  62. [71]

    & Mazzalay, X.\ 2006, , 367, L57

    Rodr \' guez-Ardila, A. & Mazzalay, X.\ 2006, , 367, L57. doi:10.1111/j.1745-3933.2006.00139.x

    2006

  63. [72]

    J., Finkbeiner, D

    Schlegel, D. J., Finkbeiner, D. P., & Davis, M.\ 1998, , 500, 525. doi:10.1086/305772

    1998 doi

  64. [73]

    doi:10.1088/0004-637X/800/2/108

    Scoville, N., Faisst, A., Capak, P., et al.\ 2015, , 800, 108. doi:10.1088/0004-637X/800/2/108

    2015 doi

  65. [74]

    cao ., Pan, X., Dou, L.-

    Shi, X.-. cao ., Pan, X., Dou, L.-. ming ., et al.\ 2020, , 44, 196. doi:10.1016/j.chinastron.2020.05.004

    2020 doi

  66. [75]

    W., & Li, A.\ 2017, , 840, 27

    Shao, Z., Jiang, B. W., & Li, A.\ 2017, , 840, 27. doi:10.3847/1538-4357/aa6ba4

    2017 doi

  67. [76]

    doi:10.1093/mnras/stac1313

    Shivaei, I., Boogaard, L., D \' az-Santos, T., et al.\ 2022, , 514, 1886. doi:10.1093/mnras/stac1313

    2022 doi

  68. [77]

    Siebenmorgen, R., Kr \"u gel, E., & Spoon, H. W. W.\ 2004, , 414, 123. doi:10.1051/0004-6361:20031633

    2004 doi

  69. [78]

    F., Cutri, R

    Skrutskie, M. F., Cutri, R. M., Stiening, R., et al.\ 2006, , 131, 1163. doi:10.1086/498708

    2006 doi

  70. [79]

    Sparke, L. S. & Gallagher, J. S.\ 2007, Galaxies in the Universe: An Introduction. Second Edition. By Linda S. Sparke and John S. Gallagher, III. ISBN-13 978-0-521-85593-8 (HB); ISBN-13 978-0-521-67186-6 (PB). Published by Cambridge University Press, Cambridge, UK, 2007

    2007

  71. [80]

    Spoon, H. W. W., Marshall, J. A., Houck, J. R., et al.\ 2007, , 654, L49. doi:10.1086/511268

    2007 doi

  72. [81]

    doi:10.1111/j.1745-3933.2008.00558.x

    Srianand, R., Gupta, N., Petitjean, P., et al.\ 2008, , 391, L69. doi:10.1111/j.1745-3933.2008.00558.x

    2008

  73. [82]

    P.\ 1965, , 142, 1683

    Stecher, T. P.\ 1965, , 142, 1683. doi:10.1086/148462

    1965 doi

  74. [83]

    M., & Padovani, P.\ 1995, , 107, 803

    Urry, C. M., & Padovani, P.\ 1995, , 107, 803. doi:10.1086/133630

    1995 doi

  75. [84]

    E., Richards, G

    Vanden Berk, D. E., Richards, G. T., Bauer, A., et al.\ 2001, , 122, 549. doi:10.1086/321167

    2001 doi

  76. [85]

    M.\ 1992, , 258, 841

    Voit, G. M.\ 1992, , 258, 841. doi:10.1093/mnras/258.4.841

    1992 doi

  77. [86]

    M., Smette, A., Fruchter, A

    Vreeswijk, P. M., Smette, A., Fruchter, A. S., et al.\ 2006, , 447, 145. doi:10.1051/0004-6361:20053795

    2006 doi

  78. [87]

    B., Ge, J., et al.\ 2004, , 609, 589

    Wang, J., Hall, P. B., Ge, J., et al.\ 2004, , 609, 589. doi:10.1086/421240

    2004 doi

  79. [88]

    doi:10.1088/0004-637X/760/1/42

    Wang, J.-G., Zhou, H.-Y., Ge, J., et al.\ 2012, , 760, 42. doi:10.1088/0004-637X/760/1/42

    2012 doi

  80. [89]

    J., Morris, S

    Weymann, R. J., Morris, S. L., Foltz, C. B., et al.\ 1991, , 373, 23. doi:10.1086/170020

    1991 doi

  81. [90]

    Whittet, D. C. B.\ 2003, Dust in the galactic environment

    2003

  82. [91]

    L., Eisenhardt, P

    Wright, E. L., Eisenhardt, P. R. M., Mainzer, A. K., et al.\ 2010, , 140, 1868. doi:10.1088/0004-6256/140/6/1868

    2010 doi

  83. [92]

    doi:10.1051/0004-6361:20030608

    Wucknitz, O., Wisotzki, L., Lopez, S., et al.\ 2003, , 405, 445. doi:10.1051/0004-6361:20030608

    2003 doi

  84. [93]

    Y., Li, A., & Zhong, J

    Xiang, F. Y., Li, A., & Zhong, J. X.\ 2011, , 733, 91. doi:10.1088/0004-637X/733/2/91

    2011 doi

  85. [94]

    Zafar, T., Watson, D., Fynbo, J. P. U., et al.\ 2011, , 532, A143. doi:10.1051/0004-6361/201116663

    2011 doi

  86. [95]

    doi:10.1088/0004-637X/753/1/82

    Zafar, T., Watson, D., El \' asd \'o ttir, \'A ., et al.\ 2012, , 753, 82. doi:10.1088/0004-637X/753/1/82

    2012 doi

  87. [96]

    E., Fynbo, J

    Zafar, T., Heintz, K. E., Fynbo, J. P. U., et al.\ 2018, , 860, L21. doi:10.3847/2041-8213/aaca3f

    2018 doi

  88. [97]

    doi:10.1088/0004-637X/714/1/367

    Zhang, S., Wang, T.-G., Wang, H., et al.\ 2010, , 714, 367. doi:10.1088/0004-637X/714/1/367

    2010 doi

  89. [98]

    doi:10.1088/0004-637X/802/2/92

    Zhang, S., Ge, J., Jiang, P., et al.\ 2015, , 802, 92. doi:10.1088/0004-637X/802/2/92

    2015 doi

  90. [99]

    doi:10.1051/0004-6361/202142476

    Zhang, S., Ge, J., Ji, T., et al.\ 2022, , 663, A63. doi:10.1051/0004-6361/202142476

    2022 doi

  91. [100]

    doi:10.1088/0004-637X/708/1/742

    Zhou, H., Ge, J., Lu, H., et al.\ 2010, , 708, 742. doi:10.1088/0004-637X/708/1/742

    2010 doi

  92. [101]

    doi:10.3847/1538-4357/aca085

    Zhou, Y., Hao, L., Jiang, P., et al.\ 2022, , 941, 111. doi:10.3847/1538-4357/aca085

    2022 doi

Pith tools

Reviewed August 7, 2026 · model on record in the stance chip above.