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Discovery of a Dense Association of Stars in the Vicinity of the Supermassive Black Hole Sgr A*

T0 review · 5 major / 5 minor · reviewed 2026-08-12 · deepseek-v4-flash

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Pith's one-line read First proper motions show the dense star group around IRS 1W is a real co-moving association.

desk verdict New proper motions and a real overdensity near IRS 1W, but the co-moving group claim rests on fragile single-star astrometry and needs a robustness test. read the letter →

arxiv 2411.08970 v1 pith:4PBIBKHN submitted 2024-11-13 astro-ph.GA astro-ph.HEgr-qc

S. Elaheh Hosseini , Andreas Eckart , Michal Zajaček , Silke Britzen , Harshitha K. Bhat , Vladimír Karas This is my paper · ORCID
classification astro-ph.GAastro-ph.HEgr-qc
keywords GalacticcenterSgrA*IRS1Wstellarassociationpropermotionsintermediate-massblackholenuclearstarclusterbowshock
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 proper-motion measurements for 42 infrared sources in a 1.35-arcsecond circle around the bow-shock star IRS 1W, about 6 arcseconds north-east of the Galactic Center black hole Sgr A*. It finds that 28 of these sources move coherently toward the north-west and are packed more densely (42 sources) than eleven comparable random fields (mean $14.6 \pm 1.5$), so the group cannot be explained as a chance alignment of unrelated stars. The authors argue that this is a co-moving association of massive, young stars, possibly the stripped core of a star cluster falling into Sgr A*, and they consider two binding mechanisms: an intermediate-mass black hole of order $10^4\,M_\odot$, or the line-of-sight projection of an inclined stellar disk. A genuine compact association at this radius would be a new probe of how young stars and intermediate-mass black holes are delivered to the Galactic Center.

What carries the argument

The load-bearing measurement is proper-motion astrometry: source positions were extracted from high-pass filtered Ks-band images in each of 16 epochs (2003.451 to 2018.311), registered to a common frame using the position of the star S2, and fitted linearly in right ascension and declination to give velocities. The NW/NE split is made by the flying-angle histogram (zero degrees is north, negative is north-west), and the clustering test compares the 42-source aperture with eleven equal-size apertures at the same distance from Sgr A*. For the IMBH scenario the virial estimate $M \sim \sigma_\star^2 R_c/G$ and the tidal-stability condition $R_c \lesssim d\,(m_{\rm NW}/3M_\bullet)^{1/3}$ set the mass scale, and an advection-dominated accretion flow (ADAF) spectral model with Bondi accretion is used to show why such an IMBH would be X-ray faint.

What would settle it

A high-resolution spectroscopic campaign measuring radial velocities of the 28 NW-ward sources would settle the claim: if their line-of-sight velocities are not coherent with the NW bulk motion, or if PSF-fitting astrometry of the same 16 epochs erases the NW/NE split, the co-moving association would be falsified.

Watch

Extended reading notes

Core claim

The central claim is that the dense stellar concentration around IRS 1W is kinematically real: using 16 epochs of Ks-band adaptive-optics imaging from 2003 to 2018, the authors measure proper motions for all 42 N-sources and find that 28 move with flying angles between roughly $-35$ and $0$ degrees (north-westward), while the remaining 14 move north-eastward. The NW subset has a Gaussian-like spatial distribution around the group center and its numbers exceed the field expectation by roughly a factor of three, whereas the NE subset is spatially flat and matches the random-field count. The paper therefore identifies the NW group as a co-moving association of massive, young stars and presents two scenarios, an IMBH of mass roughly $10^4$ to $10^5\,M_\odot$ binding the cluster, or an inclined disk-like distribution projected along the line of sight, while noting that current data do not strongly prefer either.

Load-bearing premise

The entire case rests on the assumption that the small positional shifts measured for faint stars in this crowded field, using images aligned to the reference star S2, are real motions and not systematic frame errors or source confusion.

Editorial extensions

If this is right

  • The region around IRS 1W contains a genuine stellar overdensity: 42 sources versus a mean of $14.6 \pm 1.5$ in eleven comparable apertures, so chance projection is unlikely to explain the association.
  • If the NW group is bound by an IMBH, the virial theorem and tidal stability require a central mass of roughly $10^4$ to $10^5\,M_\odot$, and that IMBH would be X-ray faint with an Eddington ratio below about $1.7 \times 10^{-6}$, radiating through an ADAF whose spectrum peaks in the infrared or radio.
  • The association could be the tidally stripped remnant core of a massive stellar cluster spiraling toward Sgr A*, with a dynamical-friction lifetime of order $3 \times 10^5$ years, making it a transient structure in the nuclear star cluster.
  • If the overdensity is a projection effect, it implies an inclined, disk-like distribution of younger He-stars and/or dust-enshrouded stars, with IRS 1W and IRS 13 marking opposite sides of the projected disk.
  • The 14 NE-moving sources are consistent with background or foreground nuclear-cluster stars, so only the NW subset should be used in future dynamical modeling of the association.

Reading between the lines

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

  • A decisive discriminator the paper leaves open is the line-of-sight velocity pattern: the IMBH scenario predicts a virialized, roughly isotropic radial-velocity dispersion for the NW group, whereas the disk-projection scenario predicts a coherent radial-velocity gradient along the disk; existing or future spectroscopy could separate these.
  • The short dynamical-friction timescale of roughly $10^5$ years makes the IMBH scenario statistically delicate unless the system is much more massive than the lower limit or is being observed at a special epoch, which may shift the balance toward the disk-projection explanation.
  • Applying the same S2-registered, high-pass-filtered astrometry to the IRS 13 region and other candidate associations would test whether similar coherent splits appear, indicating a common disk or cluster-infall process rather than a unique IRS 1W structure.
  • The claimed overdensity could be quantified as a chance probability by Monte Carlo placement of the comparison apertures; if the 42-versus-14.6 excess has a probability above a few percent, the association claim weakens even with kinematically coherent motions.
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Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

5 major / 5 minor

Summary. This paper analyzes a 1.35''-radius field located about 6.05'' north-east of Sgr A* that contains 42 near-infrared sources (N-sources) around the bow-shock source IRS 1W. The authors use 16 epochs of NACO Ks-band images (2003–2018) to measure proper motions after registering the frames on the position of S2, and H, Ks, and L' photometry to construct a colour-colour diagram. They report that 28 of the 42 sources move north-westward, that the radial distribution of these NW sources is Gaussian-like, and that the source count (42) exceeds the mean count in 11 comparison regions at similar distance (14.6 ± 1.5). They interpret the NW subsystem either as a cluster bound by a quiescent intermediate-mass black hole with mass ~10^4–10^5 M_sun, constrained by a Chandra X-ray upper limit and ADAF SEDs, or as a projection of an inclined stellar disk. The central claim is that the IRS 1W association is observed for the first time as a co-moving group of young massive stars.

Significance. If the co-moving group claim survives, the paper reports a new stellar association in the Galactic center and a plausible IMBH site, with implications for cluster infall and for the delivery of young stars to the central parsec. The study has several genuine strengths: it provides the first proper-motion catalogue for this specific region with a 15-year baseline; it defines explicit random control fields for the overdensity comparison; it uses an independent Chandra upper limit to constrain accretion models; and the ADAF modeling makes falsifiable predictions for radio/mm follow-up. However, the central discovery claim is currently limited by the astrometric registration and by the marginal proper-motion detections of faint sources, and the IMBH mass estimate depends on the same fragile kinematic data. I therefore regard this as a promising but not yet demonstrated discovery.

major comments (5)
  1. [§5 (Proper Motion; astrometric registration)] Section 5 states that "With the aid of the S2 star position in each epoch, the position of each source was transformed into the common coordinate system." A single reference star fixes only the translation between epochs; it does not constrain relative rotation, pixel scale, or optical distortion of the NACO fields. At the ~6'' offset of the N-sources from Sgr A*, even a small residual rotation or scale error produces position offsets that are a large fraction of the per-epoch shifts used to derive proper motions for the faint sources (for example, V_RA ≈ 50 km/s corresponds to ~1.3 mas/yr, i.e. ~20 mas over the baseline). The paper provides no plate solution, no distortion correction, and no test with multiple independent reference stars, so the proper motions in Table 3 inherit an unknown systematic error that directly affects the NW/NE division and the co-moving claim.
  2. [§5, Table 3 (NW/NE classification)] The partition into 28 NW and 14 NE sources is based on the sign of V_RA, but several sources assigned to the NW group have V_RA within about 2 sigma of zero (N3: −48 ± 28 km/s; N7: −63 ± 35 km/s; N18: −33 ± 17 km/s; N36: −21 ± 19 km/s; N39: −28 ± 19 km/s), and the position-angle uncertainties for faint sources reach tens of degrees (N7: −32.5° ± 49.9°; N42: −22.8° ± 21.0°). The claimed Gaussian-like flying-angle distribution of the NW group and the 28/42 split are therefore not robust to small systematic shifts or to a different inclusion threshold. The authors should report how the results change when the borderline sources are excluded, and they should fit the proper motions with a full two-dimensional covariance model rather than treating the R.A. and Dec. components independently.
  3. [§6.1, Eq. (1) (tidal-stability criterion)] The tidal-stability argument as written does not yield a lower limit on the cluster mass. From Eq. (1), m_NW ≥ 3M_•(R_c/d_NW)^3. The true distance d_NW is unknown; only d_NW ≥ 6.05'' (the projected distance) is known. Since the right-hand side decreases as d_NW increases, inserting the projected distance gives the largest possible required mass, not a lower bound on m_NW. Hence the statement "m_NW ≳ (10.3 ± 5.4) × 10^3 M_sun" and the subsequent 10^4–10^5 M_sun range are not logically justified as lower limits unless the association is assumed to lie exactly at the projected distance.
  4. [§6.1 (virial IMBH mass estimate)] The IMBH virial mass is computed from the velocity dispersion and core radius of the same 20 NW sources that were selected by their proper-motion direction and after removing eight high-velocity sources (N6, N10, N18, N24, N26, N39, N40, N42). The removal is based on the same proper-motion measurements that define the group, so the quoted sigma_RA and sigma_Dec are conditional on the classification. In addition, the correction for the "mean error" by subtracting 19.0 and 39.3 km/s in quadrature assumes Gaussian, uncorrelated position errors, which is not established for StarFinder centroids on high-pass filtered images; the escape-velocity cut also uses the total on-sky speed and ignores the unknown line-of-sight component. The resulting M_IMBH ≈ 2 × 10^4 M_sun is therefore not an independent dynamical confirmation of the group.
  5. [§3, Fig. 3 and Table 2 (overdensity comparison)] The overdensity statistic (42 sources versus 14.6 ± 1.5) is quoted as if the aperture had been fixed a priori, but the text says that the region was chosen to "encompass the stellar overabundance" (Section 3). A post-hoc selection of the densest 1.35'' field makes the comparison with random regions optimistic, and no completeness correction is applied to the source counts. I would like to see the overdensity quantified with a completeness-corrected stellar density map, or an explicit statement of how many independent aperture placements were tried. This does not by itself refute the overdensity, but it affects the strength of the association claim.
minor comments (5)
  1. [§6.2, Eq. (9)] The formula s2 = s1 − 2 sqrt(|r_in^2 − x^2|) subtracts the inner hole also for |x| > r_in, where no hole exists; the inner-radius term should vanish outside the inner radius. As written, the projected density profile in Fig. 13 is not the physical disk cross-section.
  2. [§2, Table 1] One epoch (2005.467) was taken with the S27 camera at 27 mas/pixel, while the other epochs use S13 at 13 mas/pixel. The text should state explicitly how this different pixel scale was incorporated into the common-frame transformation and the proper-motion fit.
  3. [§4, Table 5] In Table 5 the column header "K" should be "Ks", and the statement that all N-sources are detected in H, Ks, and L' is hard to reconcile with several magnitudes having uncertainties larger than 1 mag (e.g., N38, N42).
  4. [§6.1, Eq. (4)] The ADAF Eddington-ratio range depends on the power-law index p in Eq. (4), which is set to p = 0.5 without a sensitivity study; since p is a free parameter, a brief discussion of how the X-ray upper limit constrains p would be useful.
  5. [References] There are duplicated reference entries for Levin & Beloborodov (2003), Lu et al. (2008/2009), Yelda et al. (2014), and Tanner et al. (2005); these should be consolidated.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the overdensity and proper-motion measurements are independent observables, and the IMBH estimate is a standard virial/tidal inference rather than a fitted input renamed as a prediction.

full rationale

The paper's central claims are the stellar overdensity around IRS 1W and the existence of a 28-source north-westward co-moving subgroup. The overdensity is established by direct source counts in a fixed aperture (42 sources) compared with 11 random apertures at comparable distance and radius (14.6 +/- 1.5); this comparison is an external statistical check, not a quantity fitted from the N-source data. The proper motions are new measurements from 16 epochs of Ks-band images, transformed with the S2 star as a reference; while this single-reference registration is a legitimate systematic-error concern, it is not a logical circularity because the resulting velocities are not assumed in their own derivation. The NW/NE division is made from the sign of the measured RA proper motions, and the Gaussian-like spatial distribution of the NW subset is a separate geometric statement, not an input to that division. The IMBH mass estimate uses the virial theorem and the tidal-stability criterion with the measured velocity dispersion and cluster radius of the same NW sources; this is a standard dynamical estimate, and the paper does not claim to predict those stars' velocities from the mass. The X-ray upper limit is an independent Chandra observable used to constrain the accretion model, and the disk-projection scenario adopts disk geometry from the literature rather than fitting it to the N-source data. Self-citations such as Mossoux & Eckart (2017) for X-ray reduction and Eckart et al. (2013) for color-color interpretation are contextual and not load-bearing for the co-moving-group claim. The main vulnerabilities of the paper, namely the use of a single reference star, high-pass filtered positions without PSF fitting, and large uncertainties for faint sources, are correctness and robustness risks rather than circular reasoning.

Assumptions & free parameters 4 free parameters · 5 assumptions · 1 invented entities

The central claim of a co-moving stellar association rests on the astrometric quality of the proper motions and on the assumption that the N-sources are located at the Galactic Center distance. The IMBH interpretation depends on the virial theorem and the assumption that the cluster is relaxed, while the disk projection interpretation depends on adopted disk geometry. The exponential p in the accretion model and the stellar mass-loss rates are model inputs, not fitted observables.

free parameters (4)
  • Disk inclination i = 10 degrees
    Assumed for the inclined disk projection model in Section 6.2, adopted from Levin & Beloborodov (2003) and Lu et al. (2008), not fitted to the N-source data.
  • Disk outer and inner radii rout, rin = rout = 5 arcsec, rin = 1.5 arcsec
    Assumed geometry for the disk projection scenario, chosen to produce the surface density enhancement discussed in Section 6.2.
  • Accretion rate power-law index p = 0.5
    Adopted from Seepaul et al. (2022) to relate the Bondi accretion rate to the inner accretion rate in Eq. (4); a model parameter, not measured.
  • Stellar mass-loss rate mdot_w = 1e-8 to 1e-5 M_sun/yr
    Used to compute ambient density and ADAF SEDs in Section 6.1; a range of assumed values, not fitted to observations.
assumptions (5)
  • domain assumption The NW-ward flying group is a relaxed, self-gravitating system to which the virial theorem applies (M ~ sigma^2 R / G).
    Explicitly stated in Section 6.1: 'we assume that the NW-source cluster is relaxed, which may not be the case in general.' This is load-bearing for the IMBH mass estimate.
  • domain assumption The distance to the N-sources is the Galactic Center distance of 8 kpc.
    Used to convert proper motions to velocities in Section 5; if some N-sources are foreground stars, their velocities are overestimated. The paper acknowledges possible foreground contamination in Section 4.
  • standard math The SMBH mass of Sgr A* is 4e6 M_sun.
    Used in the tidal stability criterion (Eq. 1) and the dynamical friction estimate (Eq. 7), taken from the literature.
  • domain assumption The escape velocity from Sgr A* at the cluster distance is ~370 km/s.
    Used in Section 6.1 to remove 8 fast NW sources before computing the velocity dispersion; this cut affects the IMBH mass estimate.
  • standard math The empirical M_sigma relation for nuclear star clusters (Gultekin et al. 2009) provides sigma ~ 88 km/s for the dynamical friction scaling.
    Used in Eq. (7) for the IMBH inspiral timescale, a standard scaling relation.
invented entities (1)
  • Putative intermediate-mass black hole (IMBH) at the center of the NW-ward flying association
    purpose: To gravitationally bind the co-moving group of stars and prevent tidal disruption by Sgr A*; its mass is inferred as 10^4-10^5 M_sun.
    The IMBH is inferred from the same velocity dispersion and cluster radius that define the group, which is a dynamical estimate rather than an independent detection. The Chandra X-ray upper limit is a nondetection that constrains the accretion model but does not provide positive evidence for the IMBH. The paper presents the IMBH as one of two scenarios, explicitly stating that the data do not prefer it over the disk projection.

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Cite this review

Pith. "Pith review of Discovery of a Dense Association of Stars in the Vicinity of the Supermassive Black Hole Sgr A*." pith.science (2026). https://pith.science/paper/4PBIBKHN

@misc{pith2026241108970,
  author       = {Pith},
  title        = {Pith review of: Discovery of a Dense Association of Stars in the Vicinity of the Supermassive Black Hole Sgr A*},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/4PBIBKHN}},
  note         = {Machine review of arXiv:2411.08970}
}
abstract

We focus on a sample of 42 sources in the vicinity of the bow-shock source IRS 1W (N-sources), located at the distance of $6.05''$ north-east of the supermassive black hole (SMBH) Sagittarius A* (Sgr A*), within the radius of $1.35''$. We present the first proper motion measurements of N-sources and find that a larger subset of N-sources (28 sources) exhibit a north-westward flying angle. These sources can be bound by an intermediate mass black hole (IMBH) or the concentration that we observe is due to a disk-like distribution projection along the line of sight. We detect the N-sources in $H$, $K_s$, and $L$' bands. The north-westward flying sources could be a bound collection of stars. We discuss a tentative existence of an IMBH or an inclined disk distribution to explain a significant overdensity of stars. The first scenario of having an IMBH implies the lower limit of $\sim 10^4~M_\odot$ for the putative IMBH. Our measurements for the first time reveal that the dense association of stars containing IRS 1W is a co-moving group of massive, young stars. This stellar association might be the remnant core of a massive stellar cluster that is currently being tidally stripped as it inspirals towards Sgr A*. The second scenario suggests that the appearance of the N-sources might be influenced by the projection of a disk-like distribution of younger He-stars and/or dust-enshrouded stars.

Figures

Figures reproduced from arXiv: 2411.08970 by the authors.

Figure 2
Figure 2. , we show the identified sources in Ks-band. We call these sources the N-sources for simplicity. The N-sources are not only identified in the Ks-band but also in the H- and the L ′ -bands. We determined the positions of the N-sources using the StarFinder software (Diolaiti et al. 2000) in the Ks-band high-pass filtered images from 2003.451 to 2018.311 over 16 epochs. When we investigate the number of the N-sources w… view at source ↗
Figure 1
Figure 1. The image obtained in Ks-band from 2005.366 epoch. Symbol “x” denotes the position of Sgr A*. The encircled N￾sources at the projected distance of ∼ 6.05′′ with respect to Sgr A* stands for the region of our study. The brightest star in this region is the aforementioned bow￾shock source IRS 1W. We identify 42 sources including IRS 1W in the previously described region. We name the sources starting with the letter N … view at source ↗
Figure 4
Figure 4. HKL two-colour diagram. The solid blue line denotes the colors of a one-component black body at different temperatures. The red cross represents the uncertainty of the values. The red cross denotes the mean photometric uncertainties [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
Figures from the paper (11 more)
Figure 5
Figure 5. Figure 5: The Ks-band image from 2005.366 epoch with superim￾posed proper motions for each N source. Four arrows are shown for each source. The white arrows demonstrate the velocity vectors of each source including the uncertainty of the velocity angle, whereas the red arrows in…
Figure 6
Figure 6. Figure 6: Distribution of flying angles of N-sources. The zero an￾gle stands for a Northward flying angle. The negative angles in￾dicate the North-West-ward (NW) flying angles up to −35 degrees, whereas the positive angles represent the North-East-ward (NE) fly￾ing angles up to …
Figure 8
Figure 8. Figure 8: The spatial distribution of the NE-ward flying sources. The zero point of the x-axis is at the geometrical center of the N￾sources. The spatial distribution is flat within the uncertainties. on the flying-angle distribution as well as on the spatial distri￾bution of th…
Figure 10
Figure 10. Figure 10: The Chandra X-ray image from 0.5 to 8 keV. The north is up and the east to the left. Distinct X-ray bright sources are la￾belled, namely Sgr A*, IRS 13, and the pulsar wind nebula. There is no significant X-ray source at the position of the N-source asso￾ciation. The …
Figure 11
Figure 11. Figure 11: SEDs of advection-dominated accretion flows associ￾ated with the putative IMBH at the geometrical center of the NW￾ward flying sources. Different black lines stand for the accretion rates according to the legend. For comparison, we also show the SED of Sgr A* (gray do…
Figure 13
Figure 13. Figure 13: Stellar sky surface density in arbitrary units as a function of radius in the east west direction in arcseconds. Here also, the clustering at the eastern and western tips of the disk become evident. The source density is almost a factor of 2 higher than in the norther…
Figure 12
Figure 12. Figure 12: Top: Face on view of the East West (EW) stellar disk system with outer and inner radii given in the text. For the case of s1 we indicated the corresponding quantities. Bottom: The disk system is inclined by 80 degrees. The clustering at the eastern and western tips of…
Figure 14
Figure 14. Figure 14: The Ks-band from 2005.366 observation. The Ks-band image denotes eleven regions in addition to the assumed region of IRS 1W region. These eleven regions are chosen randomly in order to identify the number of sources in each one. The only criterion is the distance from…
Figure 15
Figure 15. Figure 15: The plots show the derived positions of N2 star as a function of time, along with the best-fitting proper motions. The left panel is along RA and the right panel is along Dec. The slope of each best-fitting line is given in [PITH_FULL_IMAGE:figures/full_fig_p020_15.png]
Figure 16
Figure 16. Figure 16: Gaussian fit of the spatial distribution of NW-flying sources. Name ∆α(arcsec) ∆δ (arcsec) Geometric center of N sources (42) 6.24 ± 0.47 0.25 ± 0.42 Geometric center of NW-flying sources (28) 6.21 ± 0.48 0.35 ± 0.42 Geometric center of NE-flying sources (14) 6.38 ± 0…
Figure 17
Figure 17. Figure 17: The Chandra X-ray image from 4 to 8 keV. The north is up and the east is to the left. Distinct X-ray bright sources are labelled, namely Sgr A*, IRS 13, and the pulsar wind nebula. There is no significant X-ray source at the position of the N-source association. The a…

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Works this paper leans on

96 extracted references · 21 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]

    - [1] #1 = = ^ ^ ^ .\!\!^ d .\!\!^ h .\!\!^ m .\!\!^ s .\!\!^ @mss

    thebibliography [1] 20pt to REFERENCES 6pt =0pt -12pt 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 E...

    2021

  4. [4]

    2020, , 896, 100, 10.3847/1538-4357/ab93ae

    Ali , B., Paul , D., Eckart , A., et al. 2020, , 896, 100, 10.3847/1538-4357/ab93ae

    doi:10.3847/1538-4357/ab93ae 2020

  5. [5]

    K., Maeda , Y., Morris , M., et al

    Baganoff , F. K., Maeda , Y., Morris , M., et al. 2003, , 591, 891, 10.1086/375145

    doi:10.1086/375145 2003

  6. [6]

    Balick , B., & Brown , R. L. 1974, , 194, 265, 10.1086/153242

    doi:10.1086/153242 1974

  7. [8]

    2009 b , , 697, 1741, 10.1088/0004-637X/697/2/1741

    ---. 2009 b , , 697, 1741, 10.1088/0004-637X/697/2/1741

    doi:10.1088/0004-637x/697/2/1741 2009

  8. [9]

    2010, , 708, 834, 10.1088/0004-637X/708/1/834

    Bartko , H., Martins , F., Trippe , S., et al. 2010, , 708, 834, 10.1088/0004-637X/708/1/834

    doi:10.1088/0004-637x/708/1/834 2010

Show all 96 references
  1. [10]

    E., & Neugebauer , G

    Becklin , E. E., & Neugebauer , G. 1975, , 200, L71, 10.1086/181899

    1975 doi

  2. [11]

    J., & Hansen , B

    Berukoff , S. J., & Hansen , B. M. S. 2006, , 650, 901, 10.1086/507414

    2006 doi

  3. [12]

    K., Sabha , N

    Bhat , H. K., Sabha , N. B., Zaja c ek , M., et al. 2022, , 929, 178, 10.3847/1538-4357/ac6106

    2022 doi

  4. [13]

    D., Sellgren , K., & Depoy , D

    Blum , R. D., Sellgren , K., & Depoy , D. L. 1996, , 470, 864, 10.1086/177917

    1996 doi

  5. [14]

    S., & Lin , D

    Cantiello , M., Jermyn , A. S., & Lin , D. N. C. 2021, , 910, 94, 10.3847/1538-4357/abdf4f

    2021 doi

  6. [15]

    2016, , 594, A113, 10.1051/0004-6361/201527173

    Ciurlo , A., Paumard , T., Rouan , D., & Cl \'e net , Y. 2016, , 594, A113, 10.1051/0004-6361/201527173

    2016 doi

  7. [16]

    2004, , 417, L15, 10.1051/0004-6361:20040031

    Cl \'e net , Y., Rouan , D., Gendron , E., et al. 2004, , 417, L15, 10.1051/0004-6361:20040031

    2004 doi

  8. [17]

    K., Ciurlo , A., Morris , M

    Dinh , C. K., Ciurlo , A., Morris , M. R., et al. 2024, , 167, 41, 10.3847/1538-3881/ad10a5

    2024 doi

  9. [18]

    2000, in Astronomical Society of the Pacific Conference Series, Vol

    Diolaiti , E., Bendinelli , O., Bonaccini , D., et al. 2000, in Astronomical Society of the Pacific Conference Series, Vol. 216, Astronomical Data Analysis Software and Systems IX, ed. N. Manset , C. Veillet , & D. Crabtree , 623. astro-ph/9911354

    2000 arXiv

  10. [19]

    1996, , 383, 415, 10.1038/383415a0

    Eckart , A., & Genzel , R. 1996, , 383, 415, 10.1038/383415a0

    1996 doi

  11. [20]

    2004, , 602, 760, 10.1086/381178

    Eckart , A., Moultaka , J., Viehmann , T., Straubmeier , C., & Mouawad , N. 2004, , 602, 760, 10.1086/381178

    2004 doi

  12. [21]

    2013, , 551, A18, 10.1051/0004-6361/201219994

    Eckart , A., Mu z i \'c , K., Yazici , S., et al. 2013, , 551, A18, 10.1051/0004-6361/201219994

    2013 doi

  13. [22]

    2017, Foundations of Physics, 47, 553, 10.1007/s10701-017-0079-2

    Eckart , A., H \"u ttemann , A., Kiefer , C., et al. 2017, Foundations of Physics, 47, 553, 10.1007/s10701-017-0079-2

    2017 doi

  14. [23]

    2003, , 597, L121, 10.1086/380188

    Eisenhauer , F., Sch \"o del , R., Genzel , R., et al. 2003, , 597, L121, 10.1086/380188

    2003 doi

  15. [24]

    D., van Gorkom , J

    Ekers , R. D., van Gorkom , J. H., Schwarz , U. J., & Goss , W. M. 1983, , 122, 143

    1983

  16. [25]

    2022, , 930, L12, 10.3847/2041-8213/ac6674

    Event Horizon Telescope Collaboration , Akiyama , K., Alberdi , A., et al. 2022, , 930, L12, 10.3847/2041-8213/ac6674

    2022 doi

  17. [26]

    2015, , 584, A2, 10.1051/0004-6361/201526336

    Feldmeier-Krause , A., Neumayer , N., Sch \"o del , R., et al. 2015, , 584, A2, 10.1051/0004-6361/201526336

    2015 doi

  18. [27]

    2022, , 939, 97, 10.3847/1538-4357/ac98b6

    Fragione , G. 2022, , 939, 97, 10.3847/1538-4357/ac98b6

    2022 doi

  19. [28]

    K., Gillessen , S., Dodds-Eden , K., et al

    Fritz , T. K., Gillessen , S., Dodds-Eden , K., et al. 2010, , 721, 395, 10.1088/0004-637X/721/1/395

    2010 doi

  20. [29]

    K., Chatzopoulos , S., Gerhard , O., et al

    Fritz , T. K., Chatzopoulos , S., Gerhard , O., et al. 2016, , 821, 44, 10.3847/0004-637X/821/1/44

    2016 doi

  21. [30]

    P., Bautz , M

    Garmire , G. P., Bautz , M. W., Ford , P. G., Nousek , J. A., & Ricker , George R., J. 2003, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 4851, X-Ray and Gamma-Ray Telescopes and Instruments for Astronomy., ed. J. E. Truemper & H. D. Tan...

    2003 doi

  22. [31]

    2010, Reviews of Modern Physics, 82, 3121, 10.1103/RevModPhys.82.3121

    Genzel , R., Eisenhauer , F., & Gillessen , S. 2010, Reviews of Modern Physics, 82, 3121, 10.1103/RevModPhys.82.3121

    2010 doi

  23. [32]

    2024, arXiv e-prints, arXiv:2404.03522, 10.48550/arXiv.2404.03522

    ---. 2024, arXiv e-prints, arXiv:2404.03522, 10.48550/arXiv.2404.03522

    2024 doi arXiv

  24. [33]

    2003, , 594, 812, 10.1086/377127

    Genzel , R., Sch \"o del , R., Ott , T., et al. 2003, , 594, 812, 10.1086/377127

    2003 doi

  25. [34]

    2001, , 546, L39, 10.1086/318054

    Gerhard , O. 2001, , 546, L39, 10.1086/318054

    2001 doi

  26. [35]

    M., Klein , B

    Ghez , A. M., Klein , B. L., Morris , M., & Becklin , E. E. 1998, , 509, 678, 10.1086/306528

    1998 doi

  27. [36]

    M., Duch \^e ne , G., Matthews , K., et al

    Ghez , A. M., Duch \^e ne , G., Matthews , K., et al. 2003, , 586, L127, 10.1086/374804

    2003 doi

  28. [37]

    M., & McGee , R

    Goss , W. M., & McGee , R. X. 1996, in Astronomical Society of the Pacific Conference Series, Vol. 102, The Galactic Center, ed. R. Gredel , 369

    1996

  29. [38]

    2019, The Messenger, 178, 26, 10.18727/0722-6691/5168

    GRAVITY Collaboration , Abuter , R., Accardo , M., et al. 2019, The Messenger, 178, 26, 10.18727/0722-6691/5168

    2019 doi

  30. [39]

    2019, , 625, L10, 10.1051/0004-6361/201935656

    Gravity Collaboration , Abuter , R., Amorim , A., et al. 2019, , 625, L10, 10.1051/0004-6361/201935656

    2019 doi

  31. [40]

    E., Strader , J., & Ho , L

    Greene , J. E., Strader , J., & Ho , L. C. 2020, , 58, 257, 10.1146/annurev-astro-032620-021835

    2020 doi

  32. [41]

    O., Gebhardt , K., et al

    G \"u ltekin , K., Richstone , D. O., Gebhardt , K., et al. 2009, , 698, 198, 10.1088/0004-637X/698/1/198

    2009 doi

  33. [42]

    Hansen , B. M. S., & Milosavljevi \'c , M. 2003, , 593, L77, 10.1086/378182

    2003 doi

  34. [43]

    2009, , 394, 191, 10.1111/j.1365-2966.2008.14359.x

    Hobbs , A., & Nayakshin , S. 2009, , 394, 191, 10.1111/j.1365-2966.2008.14359.x

    2009

  35. [44]

    I., Eckart, A., et al

    Jalali, B., Pelupessy, F. I., Eckart, A., et al. 2014, Monthly Notices of the Royal Astronomical Society, 444, 1205, 10.1093/mnras/stu1483

    2014 doi

  36. [45]

    N., et al

    Kunneriath , D., Eckart , A., Vogel , S. N., et al. 2012, , 538, A127, 10.1051/0004-6361/201117676

    2012 doi

  37. [46]

    J., Rieke , G

    Lebofsky , M. J., Rieke , G. H., & Tokunaga , A. T. 1982, , 263, 736, 10.1086/160545

    1982 doi

  38. [48]

    Levin, Y., & Beloborodov, A. M. 2003, The Astrophysical Journal, 590, L33–L36, 10.1086/376675

    2003 doi

  39. [49]

    Y., & Claussen , M

    Lo , K. Y., & Claussen , M. J. 1983, , 306, 647, 10.1038/306647a0

    1983 doi

  40. [51]

    R., Ghez , A

    Lu , J. R., Ghez , A. M., Hornstein , S. D., et al. 2009, , 690, 1463, 10.1088/0004-637X/690/2/1463

    2009 doi

  41. [52]

    P., Paumard, T., Stolovy, S

    Maillard, J. P., Paumard, T., Stolovy, S. R., & Rigaut, F. 2004, Astronomy and Astrophysics, 423, 155, 10.1051/0004-6361:20034147

    2004 doi

  42. [53]

    2016, in Lecture Notes in Physics, Berlin Springer Verlag, ed

    Mapelli , M., & Gualandris , A. 2016, in Lecture Notes in Physics, Berlin Springer Verlag, ed. F. Haardt , V. Gorini , U. Moschella , A. Treves , & M. Colpi , Vol. 905 (Springer International Publishing, Switzerland), 205, 10.1007/978-3-319-19416-5_6

    2016 doi

  43. [54]

    McMillan , S. L. W., & Portegies Zwart , S. F. 2003, , 596, 314, 10.1086/377577

    2003 doi

  44. [55]

    2013, Dynamics and Evolution of Galactic Nuclei (Princeton: Princeton University Press)

    Merritt , D. 2013, Dynamics and Evolution of Galactic Nuclei (Princeton: Princeton University Press)

    2013

  45. [56]

    1992, in American Institute of Physics Conference Series, Vol

    Morris , M. 1992, in American Institute of Physics Conference Series, Vol. 278, American Institute of Physics Conference Series, 21--36, 10.1063/1.44027

    1992 doi

  46. [57]

    1993, , 408, 496, 10.1086/172607

    Morris , M. 1993, , 408, 496, 10.1086/172607

    1993 doi

  47. [58]

    2017, , 603, A68, 10.1051/0004-6361/201628385

    Moser , L., S \'a nchez-Monge , \'A ., Eckart , A., et al. 2017, , 603, A68, 10.1051/0004-6361/201628385

    2017 doi

  48. [59]

    2017, Monthly Notices of the Royal Astronomical Society, 474, 3787, 10.1093/mnras/stx3026

    Mossoux, E., & Eckart, A. 2017, Monthly Notices of the Royal Astronomical Society, 474, 3787, 10.1093/mnras/stx3026

    2017 doi

  49. [60]

    2005, , 443, 163, 10.1051/0004-6361:20052819

    Moultaka , J., Eckart , A., Sch \"o del , R., Viehmann , T., & Najarro , F. 2005, , 443, 163, 10.1051/0004-6361:20052819

    2005 doi

  50. [61]

    2007, , 469, 993, 10.1051/0004-6361:20066265

    Mu z i \'c , K., Eckart , A., Sch \"o del , R., Meyer , L., & Zensus , A. 2007, , 469, 993, 10.1051/0004-6361:20066265

    2007 doi

  51. [62]

    2008, Astronomy and Astrophysics, 482, 173, 10.1051/0004-6361:20078352

    Mu z i \' c , K., Sch \" o del, R., Eckart, A., Meyer, L., & Zensus, A. 2008, Astronomy and Astrophysics, 482, 173, 10.1051/0004-6361:20078352

    2008 doi

  52. [63]

    2006, , 366, 1410, 10.1111/j.1365-2966.2005.09906.x

    Nayakshin , S., Dehnen , W., Cuadra , J., & Genzel , R. 2006, , 366, 1410, 10.1111/j.1365-2966.2005.09906.x

    2006

  53. [64]

    S., Storchi-Bergmann , T., & Eracleous , M

    Nemmen , R. S., Storchi-Bergmann , T., & Eracleous , M. 2014, , 438, 2804, 10.1093/mnras/stt2388

    2014 doi

  54. [65]

    S., Neumayer , N., & Feldmeier-Krause , A

    Nitschai , M. S., Neumayer , N., & Feldmeier-Krause , A. 2020, , 896, 68, 10.3847/1538-4357/ab8ea8

    2020 doi

  55. [66]

    1999, in Astronomical Society of the Pacific Conference Series, Vol

    Ott , T., Eckart , A., & Genzel , R. 1999, in Astronomical Society of the Pacific Conference Series, Vol. 186, The Central Parsecs of the Galaxy, ed. H. Falcke , A. Cotera , W. J. Duschl , F. Melia , & M. J. Rieke , 310

    1999

  56. [67]

    2022, , 940, L33, 10.3847/2041-8213/ac9b21

    Pacucci , F., & Loeb , A. 2022, , 940, L33, 10.3847/2041-8213/ac9b21

    2022 doi

  57. [68]

    2006, , 643, 1011, 10.1086/503273

    Paumard , T., Genzel , R., Martins , F., et al. 2006, , 643, 1011, 10.1086/503273

    2006 doi

  58. [69]

    2021, , 923, 69, 10.3847/1538-4357/ac23df

    Pei ker , F., Zaja c ek , M., Eckart , A., et al. 2021, , 923, 69, 10.3847/1538-4357/ac23df

    2021 doi

  59. [70]

    2023, , 956, 70, 10.3847/1538-4357/acf6b5

    Pei ker , F., Zaja c ek , M., Thomkins , L., et al. 2023, , 956, 70, 10.3847/1538-4357/acf6b5

    2023 doi

  60. [71]

    2024, , 970, 74, 10.3847/1538-4357/ad4098

    Pei ker , F., Zaja c ek , M., Labaj , M., et al. 2024, , 970, 74, 10.3847/1538-4357/ad4098

    2024 doi

  61. [72]

    W., Palumbo , D

    Pesce , D. W., Palumbo , D. C. M., Narayan , R., et al. 2021, , 923, 260, 10.3847/1538-4357/ac2eb5

    2021 doi

  62. [73]

    F., Baumgardt , H., McMillan , S

    Portegies Zwart , S. F., Baumgardt , H., McMillan , S. L. W., et al. 2006, , 641, 319, 10.1086/500361

    2006 doi

  63. [74]

    F., & McMillan , S

    Portegies Zwart , S. F., & McMillan , S. L. W. 2002, , 576, 899, 10.1086/341798

    2002 doi

  64. [75]

    A., Freitag , M., & G \"u rkan , M

    Rasio , F. A., Freitag , M., & G \"u rkan , M. A. 2004, in Coevolution of Black Holes and Galaxies, ed. L. C. Ho , 138. astro-ph/0304038

    2004 arXiv

  65. [76]

    Reid , M. J. 1993, , 31, 345, 10.1146/annurev.aa.31.090193.002021

    1993

  66. [77]

    P., Naab , T., Spurzem , R., et al

    Rizzuto , F. P., Naab , T., Spurzem , R., et al. 2021, , 501, 5257, 10.1093/mnras/staa3634

    2021 doi

  67. [78]

    C., Naoz , S., Sari , R., & Linial , I

    Rose , S. C., Naoz , S., Sari , R., & Linial , I. 2022, , 929, L22, 10.3847/2041-8213/ac6426

    2022 doi

  68. [79]

    2014, , 567, A21, 10.1051/0004-6361/201423657

    Sanchez-Bermudez , J., Sch \"o del , R., Alberdi , A., et al. 2014, , 567, A21, 10.1051/0004-6361/201423657

    2014 doi

  69. [80]

    2005, The Astrophysical Journal, 625, L111, 10.1086/431307

    Sch \" o del, R., Eckart, A., Iserlohe, C., Genzel, R., & Ott, T. 2005, The Astrophysical Journal, 625, L111, 10.1086/431307

    2005 doi

  70. [81]

    2009, , 502, 91, 10.1051/0004-6361/200810922

    Sch \"o del , R., Merritt , D., & Eckart , A. 2009, , 502, 91, 10.1051/0004-6361/200810922

    2009 doi

  71. [82]

    2010, , 511, A18, 10.1051/0004-6361/200913183

    Sch \"o del , R., Najarro , F., Muzic , K., & Eckart , A. 2010, , 511, A18, 10.1051/0004-6361/200913183

    2010 doi

  72. [83]

    S., Pacucci , F., & Narayan , R

    Seepaul , B. S., Pacucci , F., & Narayan , R. 2022, , 515, 2110, 10.1093/mnras/stac1928

    2022 doi

  73. [84]

    1928, , 122, 482, 10.1038/122482a0

    Shapley , H. 1928, , 122, 482, 10.1038/122482a0

    1928 doi

  74. [85]

    1969, , 158, L139, 10.1086/180451

    Spitzer , Lyman, J. 1969, , 158, L139, 10.1086/180451

    1969 doi

  75. [86]

    M., Morris, M., et al

    Tanner, A., Ghez, A. M., Morris, M., et al. 2002, The Astrophysical Journal, 575, 860, 10.1086/341470

    2002 doi

  76. [88]

    M., Morris , M

    Tanner , A., Ghez , A. M., Morris , M. R., & Christou , J. C. 2005, , 624, 742, 10.1086/429214

    2005 doi

  77. [89]

    M., Ghez , A

    Tanner , A. M., Ghez , A. M., Morris , M., & Becklin , E. E. 2003, Astronomische Nachrichten Supplement, 324, 597, 10.1002/asna.200385093

    2003 doi

  78. [90]

    U., & Moultaka , J

    Viehmann , T., Eckart , A., Sch \"o del , R., Pott , J. U., & Moultaka , J. 2006, , 642, 861, 10.1086/501345

    2006 doi

  79. [91]

    Vollmer , B., & Duschl , W. J. 2000, , 4, 581, 10.1016/S1384-1076(99)00043-3

    2000 doi

  80. [92]

    D., Gillessen , S., Stadler , J., et al

    von Fellenberg , S. D., Gillessen , S., Stadler , J., et al. 2022, , 932, L6, 10.3847/2041-8213/ac68ef

    2022 doi

  81. [93]

    D., Lu, F

    Wang, Q. D., Lu, F. J., & Gotthelf, E. V. 2006, Monthly Notices of the Royal Astronomical Society, 367, 937, 10.1111/j.1365-2966.2006.09998.x

    2006

  82. [95]

    M., Lu, J

    Yelda, S., Ghez, A. M., Lu, J. R., et al. 2014, The Astrophysical Journal, 783, 131, 10.1088/0004-637x/783/2/131

    2014 doi

  83. [96]

    1991, , 371, L59, 10.1086/186002

    Yusef-Zadeh , F., & Morris , M. 1991, , 371, L59, 10.1086/186002

    1991 doi

  84. [97]

    A., & Biretta , J

    Yusef-Zadeh , F., Roberts , D. A., & Biretta , J. 1998, , 499, L159, 10.1086/311364

    1998 doi

  85. [98]

    2020, , 903, 140, 10.3847/1538-4357/abbd94

    Zaja c ek , M., Araudo , A., Karas , V., Czerny , B., & Eckart , A. 2020, , 903, 140, 10.3847/1538-4357/abbd94

    2020 doi

  86. [99]

    M., et al

    Zhao , J.-H., Blundell , R., Moran , J. M., et al. 2010, , 723, 1097, 10.1088/0004-637X/723/2/1097

    2010 doi

  87. [100]

    R., Goss , W

    Zhao , J.-H., Morris , M. R., Goss , W. M., & An , T. 2009, , 699, 186, 10.1088/0004-637X/699/1/186

    2009 doi

  88. [101]

    2020, The Astrophysical Journal, 897, 135, 10.3847/1538-4357/ab980d

    Zhu, Z., Li, Z., Ciurlo, A., et al. 2020, The Astrophysical Journal, 897, 135, 10.3847/1538-4357/ab980d

    2020 doi

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