Pith. sign in

REVIEW 4 major objections 4 minor 215 references

Star Formation Histories of Early-type Dwarfs in Group Environment

T0 review · 4 major / 4 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read Early-type dwarf star formation is ruled by morphology, with environment secondary.

desk verdict A large, honest sample worth engaging, but the fixed 3-arcsec fiber and untested group-finder leave the quantitative SFH and environmental claims shakier than the authors suggest. read the letter →

arxiv 2507.08975 v1 pith:LNN4ZBNJ submitted 2025-07-11 astro-ph.GA

classification astro-ph.GA
keywords early-typedwarfgalaxiesstarformationhistoriesspectralsynthesiscumulativequenchingchemicalenrichmentgalaxygroupsandclustersmorphology
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 sets out to establish that the star formation history (SFH) of an early-type dwarf galaxy is governed first by its morphology and only secondarily by its environment. The authors fit 983 SDSS spectra with the STARLIGHT synthesis code, reconstructing when and from what metallicity gas the stars in five dwarf subtypes (dS0, dE, dSph, dEbc, dEbl) formed, across six environments from the field to the Virgo Cluster. They find that red subtypes (dS0, dE, dSph) assembled most of their stellar mass early and quenched rapidly, while blue subtypes (dEbc, dEbl) show extended or ongoing star formation and host extremely metal-poor stars, which they attribute to continued accretion of pristine gas. Environmental dependence is clearest in low-mass systems: field dwarfs show prolonged star formation and slow enrichment, while Virgo dwarfs quench earlier and enrich faster. The payoff, if the picture holds, is a unified view in which nature (morphology, stellar mass) and nurture (environment) jointly set the evolutionary tracks of the most numerous galaxies in the Universe.

What carries the argument

The load-bearing machinery is full spectral fitting with the STARLIGHT synthesis code: each SDSS spectrum is decomposed into a linear combination of simple stellar population (SSP) templates of different ages and metallicities, yielding luminosity- and mass-weighted fractions of stars formed in six metallicity bins from $Z = 0.0001$ to $Z = 0.05$. From these mass fractions the authors construct cumulative star formation histories (cSFHs) and read off two characteristic timescales, $\tau_{50}$ and $\tau_{90}$ (the lookback times when 50% and 90% of the stellar mass had formed), used as formation time and quenching time. Environmental membership comes from a friends-of-friends group finder using a 500 km/s velocity threshold and a linking length set by the sum of virial radii, dividing the sample into the field, poor, intermediate, and rich groups, plus the Ursa Major and Virgo clusters.

What would settle it

Recompute the cumulative star formation histories of Section 4 with the $\Delta V = 1000$ km/s group catalog the paper describes: if the field-versus-Virgo differences in quenching time ($\tau_{90}$) and in the $Z = 0.0001$ stars formed around 3.2 Gyr ago vanish when Ursa Major galaxies are reclassified as Virgo members, the environmental trends are membership artifacts. A complementary check: resolve the stellar populations of the nearest dEbc and dEbl analogues and look for an extremely metal-poor component with ages of roughly 1 to 3 Gyr, which the pristine-accretion interpretation predicts should be present.

Watch

Extended reading notes

Core claim

The central claim is that cumulative star formation histories (cSFHs) of early-type dwarfs separate cleanly by morphological subtype. dSph galaxies formed roughly 80% of their stellar mass by a lookback time near 6.3 Gyr ago and quenched earliest, around 3.3 Gyr ago, with the smallest environmental dependence, marking them as likely primordial systems. dE and dS0 galaxies quenched somewhat later, around 1 to 2 Gyr ago, and a substantial share of them show the signature of environmental transformation from late-type progenitors rather than primordial assembly. The blue subtypes stand apart: dEbc and dEbl galaxies formed a substantial fraction of their stars during a recent star-forming episode and show extremely metal-poor populations ($Z = 0.0001$) that are absent from the red subtypes, including a distinct population formed around 3.2 Gyr ago that appears in the field but not in Virgo. The authors read this as continued accretion of pristine gas in low-density environments, and contrast it with Virgo, where high-mass dwarfs enrich rapidly and form metal-rich ($Z = 0.05$) stars from recycled gas as early as 1.5 Gyr ago. Metallicity evolution is slowest in low-mass field galaxies and fastest in high-mass cluster galaxies, which grounds the paper's dual-dependence picture: morphology sets the overall shape of the SFH while environment and mass modulate its timing, duration, and chemical enrichment.

Load-bearing premise

Every environmental comparison rests on the assumption that the friends-of-friends group catalog built with a 500 km/s velocity threshold picks out the true physical groups; the paper itself reports in Section 2.2.2 that raising the threshold to 1000 km/s merges the Ursa Major cluster into Virgo and changes Virgo membership from 1068 to 1750 galaxies, yet no environmental result is checked against that alternative membership.

Editorial extensions

If this is right

  • If morphology is primary, then dSph galaxies, with early, rapid star formation and little environmental variation, can be treated as primordial relics, whereas many dS0 and dE galaxies are environmentally transformed late-type systems.
  • Environmental quenching acts most strongly in shallow potential wells: at low stellar mass, Virgo dwarfs quench far earlier than field dwarfs, while at high mass the star formation history hardly changes with environment.
  • Blue early-type dwarfs keep forming stars in every environment studied, so surveys that treat dEbc and dEbl as quiescent early-type populations will misclassify a large, actively star-forming component of the dwarf population.
  • Late-time accretion of pristine gas is a genuine channel for star formation in low-density environments and delays chemical enrichment there, whereas cluster environments suppress such inflow and instead recycle enriched gas.
  • The physical state of a cluster, illustrated by the Ursa Major versus Virgo comparison, matters for quenching, not just the number of member galaxies.

Reading between the lines

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

  • A corollary the paper leaves implicit: any dwarf sample selected by red color or red-sequence membership alone will mix primordial dSph-like galaxies, transformed dS0/dE-like galaxies, and the star-forming dEbc/dEbl population, so quenching conclusions drawn from such mixed samples inherit a selection bias.
  • The paper's own Section 2.2.2 shows that raising the group-finding velocity threshold from 500 to 1000 km/s merges Ursa Major into Virgo and grows Virgo membership from 1068 to 1750 galaxies; since all environmental trends are quoted only for the 500 km/s catalog, a re-analysis with the 1000 km/s catalog would test whether the field-versus-cluster differences are physical or membership artifacts.
  • The pristine-accretion interpretation yields a testable prediction the authors do not state: resolved stellar populations in nearby dEbc/dEbl analogues should contain an extremely metal-poor ($Z \lesssim 0.0004$) component with ages near 1 to 3 Gyr, and their cold gas reservoirs should be largely unenriched.
  • If morphological subtype really is the primary driver, then the classification itself, not environment, is the organizing variable for dwarf evolution; a next step would be to check whether the five-subtype SFH ordering persists in a sample selected independently of the CVCG catalog and its visual classifications.
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 / 4 minor

Summary. The paper presents STARLIGHT full spectral fits to SDSS DR7 spectra of 983 early-type dwarf galaxies classified into five subtypes (dS0, dE, dEbc, dSph, dEbl), and compares their derived star formation histories and metallicity distributions across six environments from the field to the Virgo Cluster. The central claim is that morphology is the primary driver of SFH shape, with environment playing a secondary but non-negligible role: red subtypes quench early, blue subtypes show extended or ongoing star formation and host extremely metal-poor stars attributed to pristine gas accretion. The analysis also examines cumulative SFHs, characteristic timescales tau50 and tau90, quenching times, and mass-environment trends.

Significance. If the main conclusions hold, the paper provides a valuable, statistically homogeneous mapping of early-type dwarf SFHs across morphology and environment, extending beyond Local Group resolved studies to a sample of nearly a thousand galaxies. The use of a common spectral fitting method, the quantitative cSFH metrics with bootstrap uncertainties, the KS-test comparisons, and the explicit documentation of the group-finder's sensitivity are strengths. The paper is also candid about the fiber-aperture limitation. However, because the key morphology-environment ordering rests on central 3-arcsec fiber spectra and a single group-finding configuration, the quantitative conclusions about the primacy of morphology and the interpretation of pristine gas accretion require additional robustness checks before the results can be regarded as secure.

major comments (4)
  1. [Section 2.1, Figures 5-9]
  2. [Section 2.2.2, Figures 8-14]
  3. [Section 3.1 and Section 5.1]
  4. [Section 5.2, Figure 14]
minor comments (4)
  1. [Throughout]
  2. [Section 2.1]
  3. [Section 3.1]
  4. [Section 4.3 and Figure 10-11]

Circularity Check

0 steps flagged · score 2.0 of 10

No significant circularity: SFHs are derived from public SDSS spectra with the external STARLIGHT code; self-citations are to the morphological input catalog and prior validation, not to the load-bearing inference.

full rationale

The paper's derivation chain is self-contained against external data and tools. SFHs are obtained by full spectral fitting of SDSS DR7 spectra with STARLIGHT (Cid Fernandes et al. 2005; Bruzual & Charlot 2003 SSPs), not from the morphological labels or from the authors' previous SFH papers. The morphological subtypes from Ann et al. (2015) are an input catalog defined from visual morphology and colors; they are not derived from the fitted SFHs, so the morphology-SFH comparison is an empirical cross-correlation rather than a definitional reduction. The cited validation (Seo & Ann 2023; Ann & Seo 2024) checks STARLIGHT's reliability, including a pPXF cross-comparison, and is not the basis of the central claim. The acknowledged color-based definitions of dEbc/dEbl mean that their blue colors already hint at young stellar populations, so the qualitative statement that blue subtypes have extended star formation is partly an expected selection effect; however, the quantitative cSFHs, tau_50/tau_90 timescales, and the non-trivial red-subtype distinctions (e.g., dSph earliest quenching) carry independent content. The fixed 3-arcsec SDSS fiber and the Delta V = 500 km/s group-finder sensitivity are documented limitations or robustness concerns, not circularities, because no fitted parameter is being relabeled as a prediction. No circular step can be exhibited from the paper's equations.

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

The central claims rest on two classes of inputs: standard spectral fitting assumptions (SSP libraries, [alpha/Fe] = 0, STARLIGHT recoverability) and the adopted group-finding configuration (velocity threshold 500 km/s, limiting magnitude -15.2, virial-radius linking length). The paper validates the spectral fitting only through its own prior tests and a pPXF comparison with a 0.3 dex metallicity offset, and it validates the group finding only by listing how membership changes with the velocity threshold, not by testing the stability of its scientific conclusions.

free parameters (6)
  • Group-finding velocity threshold Delta V = 500 km/s
    Hand-chosen linking velocity in the friends-of-friends algorithm. The paper shows that changing it to 1000 km/s merges Ursa Major into Virgo and changes group memberships substantially (Section 2.2.2), so all environmental comparisons depend on this choice.
  • Background density limiting magnitude M_lim = -15.2
    Adopted to define a volume-limited sample within z = 0.01 for the nearest-neighbor density calculation, which affects the field/group density assignment (Section 2.2.2).
  • Red sequence baseline fit = Linear fit to dS0, dE, and dSph galaxies in the u-r versus M_r plane
    Used to define D/sigma, the color deviation from the red sequence, characterizing subtypes in Figure 1. Not used in SFH derivation directly, but underpins subtype color interpretations.
  • Mass bin boundaries for Figure 14 = Median stellar mass plus or minus one standard error
    Chosen to split low- and high-mass galaxies. The boundaries are derived from the sample itself and are not justified independently; results may be sensitive to this choice.
  • 3 sigma clipping thresholds = 3 sigma
    Applied iteratively when computing median tau_BB - tau_50 and tau_50 - tau_90 and in regression fits (Sections 4.3, 4.4). The paper notes that for dEbc galaxies many late-quenching members are excluded by this clipping, which changes the reported slope.
  • STARLIGHT fitted extinction A_V and velocity dispersion sigma per galaxy = Fitted per galaxy
    These are standard parameters fitted by STARLIGHT to each spectrum. They are inputs to the derived SFHs and metallicities, and their uncertainties are not propagated into the quoted age and metallicity distributions.
assumptions (6)
  • domain assumption STARLIGHT spectral synthesis correctly recovers stellar ages and metallicities from SDSS spectra of early-type dwarfs.
    Invoked across Section 2.2.1 and throughout the paper. The authors validate it using their own mock tests (Seo & Ann 2023) and a pPXF comparison (Ann & Seo 2024), which shows a 0.3 dex systematic offset in metallicity, so the assumption is only partially supported.
  • domain assumption Bruzual & Charlot (2003) SSP models with [alpha/Fe] = 0 and six metallicity bins adequately represent the stellar populations of early-type dwarfs.
    These models are the basis of the STARLIGHT fits (Section 2.2.1). Simplifications such as fixed alpha enhancement and discrete metallicity bins could bias derived metallicities and SFH shapes.
  • domain assumption SDSS 3-arcsecond fiber spectra are representative of the central stellar populations, and aperture corrections yield reliable total stellar masses.
    Section 2.1 notes the fiber diameter is smaller than the galaxy extent, so spectra reflect central regions only. Stellar masses are derived from model fluxes with an aperture correction from Ann & Seo (2024), but the correction is not independently validated here.
  • domain assumption The friends-of-friends algorithm with Delta V = 500 km/s and virial-radius linking length identifies physically associated galaxy groups.
    Section 2.2.2 describes the group finding. The paper documents that membership changes dramatically with the velocity threshold but does not test whether the scientific conclusions are robust to this choice.
  • domain assumption Morphological subtypes from Ann et al. (2015) correspond to physically meaningful classes.
    The entire analysis is stratified by these subtypes, which were defined in the authors' own catalog. The paper does not test alternative classification schemes.
  • ad hoc to paper The absence of stars with Z = 0.0001 in red early-type dwarfs indicates pre-enrichment rather than a spectral fitting artifact.
    Section 5.1 interprets the metallicity floor as evidence of Population III pre-enrichment. Given the known age-metallicity degeneracy and the STARLIGHT metallicity offset, this interpretation is not uniquely forced by the data.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Star Formation Histories of Early-type Dwarfs in Group Environment." pith.science (2026). https://pith.science/paper/LNN4ZBNJ

@misc{pith2026250708975,
  author       = {Pith},
  title        = {Pith review of: Star Formation Histories of Early-type Dwarfs in Group Environment},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/LNN4ZBNJ}},
  note         = {Machine review of arXiv:2507.08975}
}
read the original abstract

We investigate the star formation histories (SFHs) of 983 early-type dwarf galaxies classified into five morphological subtypes, dS0, dE, dEbc, dSph, and dEbl,across six environments ranging from the field to rich clusters such as Ursa Major and Virgo. Using full spectral fitting of SDSS spectra with the starlight code, we derive detailed SFHs and chemical enrichment patterns. We find that SFHs are primarily shaped by morphology, with environment playing a secondary but non-negligible role. Red early-type dwarfs (dS0, dE, dSph) typically formed most of their stars early and quenched rapidly, whereas blue early-type dwarfs (dEbc, dEbl) exhibit extended or ongoing star formation and host extremely metal-poor stars, suggesting continued pristine gas accretion. Environmental dependence is clearest in low-mass systems: field galaxies often show prolonged SFHs and delayed enrichment, while Virgo Cluster galaxies tend to quench earlier and enrich more rapidly. Cumulative SFHs reinforce these trends, with dSph galaxies showing the earliest quenching and least environmental dependence, indicating a likely primordial origin. Metallicity evolution also varies with mass and environment, progressing most slowly in low-mass field galaxies and most rapidly in high-mass cluster galaxies. Our results highlight the combined influence of morphology, stellar mass, and environment on the evolutionary diversity of early-type dwarfs, and suggest that both internal processes (nature) and external conditions (nurture) are intricately linked in shaping their star formation and chemical enrichment histories.

Figures

Figures reproduced from arXiv: 2507.08975 by the authors.

Figure 1
Figure 1. a) Colour–magnitude diagram for early-type dwarf galax￾ies. The five subtypes are distinguished by symbols and colours as indicated in the legend. The dotted black line shows the linear fit to the combined distribution of dS0, dE, and dSph galaxies, which defines the fiducial red sequence. (b) Mean deviation from the red sequence, normalised by the RMS dispersion (D/σ), for each mor￾phological subtype. We used SDSS … view at source ↗
Figure 2
Figure 2. Spectrum of two sample galaxies IC 3653 and MCG+10- 15-083. We plot observed spectra in black and the model spectra in red. Observed and model fluxes are normalized by the flux at λ0 = 4020 ˚A. pPXF. A similar discrepancy was reported by Mentz et al. (2016) for the dE galaxy NGC 1396 in the Fornax Cluster. Stellar masses were derived from the model fluxes obtained through STARLIGHT, using galaxy distances listed in … view at source ↗
Figure 4
Figure 4. Fraction of dwarf galaxy types as a function of the num￾ber of group members. The dwarf types are adopted from CVCG (Ann et al. 2015): dS0 (dwarf lenticular), dE (dwarf elliptical), dEbc(blue-cored dwarf elliptical), dSph (dwarf spheroidal) and dEb(blue dwarf elliptical). ground density was normalized by the mean surface density of the local universe, Σ. Figure ¯ 3 displays the distribution of normalized background … view at source ↗
Figures from the paper (10 more)
Figure 5
Figure 5. Figure 5: Stellar mass fractions as a function of stellar age, separated by morphological type. The contributions from different metallicities are color-coded as follows: Z = 0.0001 (blue), Z = 0.0004 (cyan), Z = 0.004 (green), Z = 0.008 (brown), Z = 0.02 (magenta) and Z = 0.05 …
Figure 6
Figure 6. Figure 6: Star formation histories (SFHs) of early-type dwarf galaxies across six different environments: field, poor group, intermediate group, rich group, UMa Cluster, and Virgo Cluster. Each panel shows the distribution of stellar mass fraction as a function of stellar age (i…
Figure 7
Figure 7. Figure 7: Luminosity-weighted mean metallicity (Z) as a function of luminosity-weighted mean stellar age. Morphological types are distinguished by different symbols and colors. yet the few stars formed during this epoch are predominantly extremely metal-rich (Z = 0.05). Recent s…
Figure 8
Figure 8. Figure 8: Cumulative star formation histories (cSFHs) of early-type dwarf galaxies in different group environments. Morphological types are distinguished by colors, as indicated in the legend. In poor group environments, the relative differences in star formation rates among ear…
Figure 9
Figure 9. Figure 9: Cumulative star formation histories (cSFHs) of early-type dwarf galaxies, divided by morphological type. Different environments are distinguished by colors, as indicated in the legend. The final panel (bottom-right) of [PITH_FULL_IMAGE:figures/full_fig_p010_9.png]
Figure 10
Figure 10. Figure 10: Star formation histories of early-type dwarf galaxies by environment. Each panel shows the median values of τBB − τ50 (x-axis) and τ50 − τ90 (y-axis) for different morphological subtypes (coloured symbols). Here, the terms τ50 and τ90 indicate the lookback times when …
Figure 11
Figure 11. Figure 11: Star formation histories of early-type dwarf galaxies by morphological subtype. Each panel shows the median values of τBB −τ50 (x-axis) and τ50 − τ90 (y-axis) for a given subtype, with different environments distinguished by colour. Error bars indicate the 68% bootstr…
Figure 12
Figure 12. Figure 12: Quenching time (log(τ90)) versus stellar mass for each subtype of early-type dwarf galaxies. The black short-dashed lines indicate the regression fits with 3σ clipping for each subtype, while the green line shows the global regression fit. Pearson correlation coeffici…
Figure 13
Figure 13. Figure 13: Cumulative star formation histories of early-type dwarf galaxies in the Virgo Cluster, divided into inner (r < rm) and outer (r > rm) regions, where rm is the mean clustercentric distance of the Virgo member galaxies. Solid lines represent the mean cSFHs and dotted li…
Figure 14
Figure 14. Figure 14: Stellar mass fractions of dS0, dEbc and dSph galaxies in the field (left panels) and in the Virgo Cluster (right panels). Contributions from different metallicities are color-coded as indi￾cated in the legend. galaxies during this phase. The infalling pristine gas mix…

Discussion (0). Sign in to comment.

Reference graph

Works this paper leans on

215 extracted references · 79 canonical work pages

  1. [1]

    G., Moore, B., Bower, R

    Abadi, M. G., Moore, B., Bower, R. G., 1999, MNRAS, 308, 947

  2. [2]

    Aguerri, J. A. L., Iglesias-Páramo, J., Vílchez, J. M., Muñoz-Tuñón, C., Sánchez-Janssen, R. , 130, 475

  3. [3]

    B., 2014, , 47, 1

    Ann H. B., 2014, , 47, 1

  4. [4]

    B., Seo, M., Ha, D

    Ann, H. B., Seo, M., Ha, D. K., 2015, , 217, 27

  5. [5]

    B., 2017, , 50,111

    Ann, H. B., 2017, , 50,111

  6. [6]

    B., Seo, M

    Ann, H. B., Seo, M. 2024, MNRAS, 530, 210

  7. [7]

    Aparicio, A., Carrera, R., Martínez-Delgado, D., 2001, , 122, 2524

  8. [8]

    V., , 2007, , 381, 263

    Asari, N. V., , 2007, , 381, 263

Show all 215 references
  1. [9]

    I., Smith, R., 2103, , 432, 274

    Assmann, P., Fellhauer, M., Wilkinson, M. I., Smith, R., 2103, , 432, 274

  2. [10]

    Bacon R. et. al. 2010, SPIE, 7735, 08

  3. [11]

    D., Binggeli, B., Jerjen, H., 2002, A&A, 391, 823

    Barazza, F. D., Binggeli, B., Jerjen, H., 2002, A&A, 391, 823

  4. [12]

    D., Binggeli, B., Jerjen, H., 20023 A&A, 40 7, 121

    Barazza, F. D., Binggeli, B., Jerjen, H., 20023 A&A, 40 7, 121

  5. [13]

    Barkana, R., Loeb, A., 1999, , 523, 54

  6. [14]

    H., Fan, X., White, R

    Becker, R. H., Fan, X., White, R. L. et al., 2001, AJ, 122, 2850

  7. [15]

    F., Abadi, M

    Benitez-Llambay, A., Navarro, J. F., Abadi, M. G. et al., 2013, ApJ, 763, L41

  8. [16]

    F., Abadi, M

    Benitez-Llambay, A., Navarro, J. F., Abadi, M. G. et al., 2015, , 450, 4207

  9. [17]

    L., Cassisi, S., Aparicio, A., Piotto, G., 2018, , 476, 718

    Bettinelli, M., Hidalgo, S. L., Cassisi, S., Aparicio, A., Piotto, G., 2018, , 476, 718

  10. [18]

    L., Cassisi, S., Aparicio, A., Piotto, G., Valdes, F., Walker, A

    Bettinelli, M., Hidalgo, S. L., Cassisi, S., Aparicio, A., Piotto, G., Valdes, F., Walker, A. R., 2019, , 487, 5862

  11. [19]

    M., 1991, A&A, 252, 27

    Binggeli, B., & Cameron, L. M., 1991, A&A, 252, 27

  12. [20]

    M., 1993, 98, 297

    Binggeli, B., & Cameron, L. M., 1993, 98, 297

  13. [21]

    C., 1995, 298, 63

    Binggeli, B., & Popescu, C. C., 1995, 298, 63

  14. [22]

    Binggeli, B., Sandage, A., & Tammann, G. A. 1985, AJ, 90, 1681

  15. [23]

    R., Faber, S

    Blumenthal, G. R., Faber, S. M., Primack, J. R., Rees, M. J., 1985, Nature, 313, 72

  16. [24]

    Boselli, A., Boissier, S., Cortese, L., Gavazzi, G., 2008, , 674, 742

  17. [25]

    Boselli, A., Fossati, M., Sun, M., 2022, The Astronomy and Astrophysics Review, 30, 3

  18. [26]

    S., Ricotti, M., 2009, ApJ, 693, 1859

    Bovill, M. S., Ricotti, M., 2009, ApJ, 693, 1859

  19. [27]

    , 2012, , 427, 127

    Bressanm A. , 2012, , 427, 127

  20. [28]

    D., Tremoni, C., Kauffmann, G., Hexkman, T., Brinkmann, J., 2004, , 351, 1151

    Brinchmann, J., Charlot, S., Whitw, S. D., Tremoni, C., Kauffmann, G., Hexkman, T., Brinkmann, J., 2004, , 351, 1151

  21. [29]

    Bromm, Volker; Yoshida, Naoki; Hernquist, Lars; McKee, Christopher F., 2009, nature, 459, 498

  22. [30]

    M., 2014, , 796, 91

    Brown,T. M., 2014, , 796, 91

  23. [31]

    Bruzual, G.; Charlot, S., 2003, , 344, 1000

  24. [32]

    Buta, R. J. 2011, arXiv 1102- 0550

  25. [33]

    Buta, R. J. 2013, in Planets, Stars and Stellar Systems, vol 6, ed. Terry D. Oswalt, & Willuam, C. Keel (New York: Springer Science+Business Media Dordrechr), 1

  26. [34]

    Buta, R. J. , 2015, , 217, 32

  27. [35]

    Buyle, P., De Rijcke, S., Michielsen, D., Baes, M., Dejonghe, H., 2005, , 360, 853

  28. [36]

    M., Moretti, A., Fritx, J., Fasanp, G., 2018, , 481, 3456

    Calvi, R., Vulcani, B., Poggianto, B. M., Moretti, A., Fritx, J., Fasanp, G., 2018, , 481, 3456

  29. [37]

    Cappellari, M., 2017, , 466, 798

  30. [38]

    Cappellari, M., Emsellem, E., 2004, , 116, 138

  31. [39]

    A., Clayton, G

    Cardelli, J. A., Clayton, G. C., Mathis, J. S., 1989, , 345, 245

  32. [40]

    Carrera, R., Aparicio, A., Martínez-Delgado, D., Alonso-García, J., 2002, , 123, 3199

  33. [41]

    Chung, J., Rey, S.-C., Sung, E.-C.,Kim, S., Lee, Y., Lee, W., 2019, , 879, 97

  34. [42]

    Chung, J., Kim, S., Rey, S.-C., Lee, Y., 2021, , 923, 235

  35. [43]

    F., Prugniel, P

    Chilingarian, I., Cayatte, V., Durret, F., Adami, C., Balkowski, C., Chemin, L., Lagana, T. F., Prugniel, P. 2008, , 486, 85

  36. [44]

    2009, Sci, 326, 1379

    Chilingarian, I., Cayatte, V., Revaz, Y., et al. 2009, Sci, 326, 1379

  37. [45]

    S., 2010

    Choi, Y.-Y., Han, D.-H., Kim, S. S., 2010. , 43, 191

  38. [46]

    Cid Fernandes, R., Gonzalez. D. R. M., Schmitt, H., Storchi-Bergmann, T., Martins, L. P., Perez, E., Heckman, T., Leitherer, C., Schaerer, D., , 605, 105

  39. [47]

    M., 2005, , 358, 363

    Cid Fernandes, R., Mateus, A., Sodre, L., Stasiriska, G., Gomes, J. M., 2005, , 358, 363

  40. [48]

    , 2013, , 557, 86

    Cid Fernandes, R. , 2013, , 557, 86

  41. [49]

    Cid Fernandes, R., 2018, , 480, 4480

  42. [50]

    , 2019, , 887, 112

    Cignoni, M. , 2019, , 887, 112

  43. [51]

    Conselice, C., O¡¯Neil, K., Gallagher, J., Wyse, R., 2003, , 591, 167

  44. [52]

    L., Songaila, A., Hu, E

    Cowie, L. L., Songaila, A., Hu, E. M., Cohen, J. G. 1996, , 112, 839

  45. [53]

    L., Songaila, A., 1998, Nature, 394, 44

    Cowie, L. L., Songaila, A., 1998, Nature, 394, 44

  46. [54]

    Croom, S. M. , 2012, , 421, 872

  47. [55]

    , 2007, , 670, 156

    Daddi, E. , 2007, , 670, 156

  48. [56]

    W., Shull, J

    Danforth, C. W., Shull, J. M., 2008, , 679, 194

  49. [57]

    et al., 2018, , 480, 1740

    Dawoodbhoy, T. et al., 2018, , 480, 1740

  50. [58]

    J., 1976, ApJ, 208, 13

    Davis M., Geller M. J., 1976, ApJ, 208, 13

  51. [59]

    de Boer, T. J. L., Tolstoy, E., Hill, V., Saha, A., Olszewski, E. W., Mateo, M., Starkenburg, E., Battaglia, G., Walker, M. G., 2012, A&A, 544, 73

  52. [60]

    de Boer, T. J. L., Tolstoy, E., Lemasle, B., Saha, A., Olszewski, E. W., Mateo, M., Irwin, M. J., Battaglia, G., 2014, A&A, 572, 10

  53. [61]

    W., Hau, G

    De Rijcke, S., Dejonghe, H., Zeilinger, W. W., Hau, G. K. T. 2003, A&A, 119, 125

  54. [62]

    W., & Hau, G

    de Rijcke, S., Michielsen, D., Dejonghe, H., Zeilinger, W. W., & Hau, G. K. T., 2005, A&A, 438, 491

  55. [63]

    Dekel A., Silk J., 1986, ApJ, 303, 39

  56. [64]

    , 2007, , 374, 809

    De Lucia, G. , 2007, , 374, 809

  57. [65]

    F., Fattahi, A., Simpson, C

    Digby, R., Navarro, J. F., Fattahi, A., Simpson, C. M., Oman, K. A., Gomez, F. A., Frenk, C. S., Grand, R. J. J., Pakmor, R., 2019, , 485, 5423

  58. [66]

    E., 2002, , 332,91

    Dolphin, A. E., 2002, , 332,91

  59. [67]

    A., Peter, A

    Dooley, G. A., Peter, A. H. G., Yang, T., Willman, B., Griffen, B. F., Frebel, A., 2017, , 471, 4894

  60. [68]

    1980, , 236, 351

    Dressler, A. 1980, , 236, 351

  61. [69]

    Durrell, P. R. 1997, , 113, 531

  62. [70]

    L., Mac Low, M.-M., 2019, , 482, 1304

    Emerick, A., Bryan, G. L., Mac Low, M.-M., 2019, , 482, 1304

  63. [71]

    F., Frenk, C

    Fattahi, A., Navarro, J. F., Frenk, C. S., Oman, K. A., Sawala, T., Schaller, M., 2018, , 476, 3816

  64. [72]

    Ferrara, A., Tolstoy, E., 2000, , 313, 291

  65. [73]

    , 2006, , 164, 33

    Ferrarese, L. , 2006, , 164, 33

  66. [74]

    et al., 2017, , 472, 2945

    Fitts, A. et al., 2017, , 472, 2945

  67. [75]

    D., Kirby, E

    Frebel, A., Simon, J. D., Kirby, E. N., 2014, , 2014, 786, 74

  68. [76]

    , 2021, ,909,192

    Gallart, C. , 2021, ,909,192

  69. [77]

    , 2015, , 811, L18

    Gallart, C. , 2015, , 811, L18

  70. [78]

    M., Tremonti, C., A2006, , 362, 41

    Gallazzi, A, Charlot, S., Brinchmann, J., White, Simon D. M., Tremonti, C., A2006, , 362, 41

  71. [79]

    M., A2008, , 383, 1439

    Gallazzi, A, Brinchmann, J., Charlot, S., White, Simon D. M., A2008, , 383, 1439

  72. [80]

    , 2019, , 489, 45

    Garrison-Kimmel, S. , 2019, , 489, 45

  73. [81]

    Gavazzi, G., Boselli, A., Cortese, L., Arosio, I., Gallazzi, A., Pedotti, P., Carrasco, L., 2006, , 446, 839

  74. [82]

    Astrophys, 12, 485

    Ge, C., Gu, Q.-S., 2012, Research in Astron. Astrophys, 12, 485

  75. [83]

    P., 2002, , 124, 3087

    Geha, M., Guhathakurta, P., van der Marel, R. P., 2002, , 124, 3087

  76. [84]

    P., 2003, , 126, 1794

    Geha, M., Guhathakurta, P., van der Marel, R. P., 2003, , 126, 1794

  77. [85]

    P., Guhathakurta, P., et al

    Geha, M., van der Marel, R. P., Guhathakurta, P., et al. 2010, ApJ, 711, 361

  78. [86]

    Y., 2000, , 542, 535

    Gnedin, N. Y., 2000, , 542, 535

  79. [87]

    W., Guzman, R., 2003, AJ 125, 2936

    Graham, A. W., Guzman, R., 2003, AJ 125, 2936

  80. [88]

    W., , 2017, , 840, 68

    Graham, A. W., , 2017, , 840, 68

  81. [89]

    W., Jerjen, H., Guzman, R., 2003, AJ 126, 1787

    Graham, A. W., Jerjen, H., Guzman, R., 2003, AJ 126, 1787

  82. [90]

    Graham, A. W. . 2019, , 487, 4999

  83. [91]

    K., Gallagher, J

    Grebel, E. K., Gallagher, J. S. III, van der Marvel, R. P., 2003, , 125, 1926

  84. [92]

    Gu, Q., Zhao, Y., Shi, L., Peng, Z., Luo, X., 2006, , 131, 806

  85. [93]

    , 2015, , 450, 2749

    Guglielmo, V. , 2015, , 450, 2749

  86. [94]

    E., Gott, III J

    Gunn J. E., Gott, III J. R., \ 1972, ApJ, 176, 1

  87. [95]

    , 2012, , 144, 87

    Hallenbeck, G. , 2012, , 144, 87

  88. [96]

    , 2019, , 625, 94

    Hamraz, E. , 2019, , 625, 94

  89. [97]

    Hartwick, F. D. A., 1876, , 209, 418

  90. [98]

    Hernandez, X., Gilmore, G., Valls-Gabaud, D., 2000, , 317, 8

  91. [99]

    Irwin, M

    Helmi, A. Irwin, M. J., Tolstoy, E. , 2006, , 651, L12

  92. [100]

    L., 2012, ASP Conference Series, 458, 287

    Hidalgo, S. L., 2012, ASP Conference Series, 458, 287

  93. [101]

    L., , 2013, , 778, 103

    Hidalgo, S. L., , 2013, , 778, 103

  94. [102]

    W., 1963, ,68, 691

    Hodge, P. W., 1963, ,68, 691

  95. [103]

    W., 1973, , 182, 671

    Hodge, P. W., 1973, , 182, 671

  96. [104]

    P., Geller, M

    Huchra, J. P., Geller, M. J., 1082, , 257, 423

  97. [105]

    2012, , 745, L24

    Janz, J., . 2012, , 745, L24

  98. [106]

    2014, , 786, 105

    Janz, J., . 2014, , 786, 105

  99. [107]

    H., Milosavljevic, M., 2015, , 452,1152

    Jeon, M., Bromm, V., Pawlik, A. H., Milosavljevic, M., 2015, , 452,1152

  100. [108]

    Jeon, M., Besla, G., Bromm, V., 2017, , 848, 85

  101. [109]

    2000, A&A, 358, 849

    Jerjen, H., Kalnajs, A., Binggeli, B. 2000, A&A, 358, 849

  102. [110]

    2001, in ASP Conf

    Jerjen, H., Kalnajs, A., Binggeli, B. 2001, in ASP Conf. Ser. 230, Galaxy Disks and Disk Galaxies, ed. J. G. Funes & E. M. Corsini (San Francisco, CA: ASP), 239

  103. [111]

    Joshi, G. D. , 2021, arXiv:2101.12226

  104. [112]

    D., Makarov, D

    Karachentsev, I. D., Makarov, D. I., 2013, , 145, 101

  105. [113]

    D., Kaisina, E

    Karachentsev, I. D., Kaisina, E. I., Makarov, D. I., 2013, , 147, 13

  106. [114]

    , 2003, , 341, 54

    Kauffmann, G. , 2003, , 341, 54

  107. [115]

    , 2004, , 353, 713 Kazantzidis, S., Mayer, L., Callegari, S., Dotti, M., Moustakas, L

    Kauffmann, G. , 2004, , 353, 713 Kazantzidis, S., Mayer, L., Callegari, S., Dotti, M., Moustakas, L. A., 2017, , 836, L13

  108. [116]

    A., 2017, , 836, L13

    Kazantzidis, S., Mayer, L., Callegari, S., Dotti, M., Moustakas, L. A., 2017, , 836, L13

  109. [117]

    -H., Ann, H

    Kim, K.- H., Lee, K. -H., Ann, H. B. 2006, JKAS, 39, 57

  110. [118]

    T., 2010, , 721, 72

    Kim,S., Rey, S.-C., Lisker, T., Sohn, S. T., 2010, , 721, 72

  111. [119]

    Kim,S., , 2014, , 215, 22

  112. [120]

    Koppen, J., Jachym, P., Taylor, R., Palou?, J., 2018, , 479, 436

  113. [121]

    V., Gnedin, O

    Kravtsov, A. V., Gnedin, O. Y., Klypin, A. A., 2004, , 609, 482

  114. [122]

    Kormendy, J., & Bender, R., 2012, , 198, 2

  115. [123]

    G., Yuk, I.-S., Park, H

    Lee, M. G., Yuk, I.-S., Park, H. S., Harris, J., Zaritsky, D., 2009, , 703, 692

  116. [124]

    Lisker, T., Glatt, K., Westera, P., Grebel, Eva K., 2006, , 132, 2432

  117. [125]

    K., Binggeli, B., Glatt, K., 2007, , 660, 1186

    Lisker, T., Grebel, E. K., Binggeli, B., Glatt, K., 2007, , 660, 1186

  118. [126]

    Lisker, T., Fuchs, B., 2009, , 501, 429

  119. [127]

    L., Ebrova, I., del Pino, A., & Semczuk, M

    Lokas, E. L., Ebrova, I., del Pino, A., & Semczuk, M. 2014b, MNRAS, 445, L6

  120. [128]

    M., Miller, B

    Lotz, J. M., Miller, B. W., Ferguson, H. C., 2004, , 613, 262

  121. [129]

    Gladis , , 127, 16

    Magris, C. Gladis , , 127, 16

  122. [130]

    I., Karachentsev, I., 2011, , 412, 2498

    Makarov, D. I., Karachentsev, I., 2011, , 412, 2498

  123. [131]

    I., Sharina, M

    Makarov, D. I., Sharina, M. E., Karachentseva, V. E., Karachentseva, I. G., 2015, , 581, 82

  124. [132]

    N., Makarov, D

    Makarova, L. N., Makarov, D. I., Karachentsev, I. D., Tully, R. B., Rizzi, L., 2017, , 464, 2281

  125. [133]

    Marcolini, A., D'Ercole, A., Brighenti, F., Recchi, S., 2006, , 371, 643

  126. [134]

    Mayer, L., Governato, F., Colpi, M., Moore, B., Quinn, T., Wadsley, J., Stadel, J., Lake, G., 2001, , 547, L123

  127. [135]

    Mayer, L., Governato, F., Colpi, M., Moore, B., Quinn, T., Wadsley, J., Stadel, J., Lake, G., 2001, , 559, 754

  128. [136]

    Mentz, J. J. , 2016, , 463, 2819

  129. [137]

    , 2022, , 164, 18

    Michea, J. , 2022, , 164, 18

  130. [138]

    , 2010, , 720, 1225

    Monelli, M. , 2010, , 720, 1225

  131. [139]

    , 2010, , 722, 1864

    Monelli, M. , 2010, , 722, 1864

  132. [140]

    W., , 144, 4

    McConnachie, A. W., , 144, 4

  133. [141]

    Moore, B., Katz N., Lake, G., Dressler, A., Oemler, A., \ 1996, Nature, 379, 613

  134. [142]

    Moore, B., Lake, G., Katz, N., 1998, , 495, 139

  135. [143]

    , , 645, 92

    Muller, O. , , 645, 92

  136. [144]

    Navabi, M., , 2021, , 910, 127

  137. [145]

    F., Frenk, C

    Navarro, J. F., Frenk, C. S., White, S. D. M., 1997, ApJ, 490, 493

  138. [146]

    Noeske, K. H. , 2007, , 660, L43

  139. [147]

    Jr., 1974, , 194, 1

    Oemler, A. Jr., 1974, , 194, 1

  140. [148]

    Pak, M., Rey, S.-C., Lisker, T., Lee, ., Kim, S., Sung, E.-C.., Jerjen, H., Chung, J., 2014, MNRAS, 445, 630

  141. [149]

    Pallottini, A., Ferrara, A., Gallerani, S., Salvadori, S., D'Odorico, V., 2014,2014, , 440, 2498

  142. [150]

    Park, C., Gott III, R., Choi, Y.-Y., 2008, , 674, 784d

  143. [151]

    H., 2014, , 796, L14

    Paudel, S., Ree, C. H., 2014, , 796, L14

  144. [152]

    Pedraz, S., Gorgas, J., Cardiel, N., Sanchez-Blazquez, P., Guzman, R., 2002, , 332, L59

  145. [153]

    Peebles, P. J. E., 1979, , 84, 730

  146. [154]

    Peletier, R. F. 1993, , 271, 51

  147. [155]

    Y., Ho, L

    Peng, C. Y., Ho, L. C., Impey, C. D., Rix, H. -W., 2010, , 139, 2097

  148. [156]

    J.,Forbes, D

    Penny, S. J.,Forbes, D. A., Pimbblet, K. A., Floyd, D. J. E., 2014, , 443, 3381

  149. [157]

    J., Masters, K

    Penny, S. J., Masters, K. L., Weijmans, A.-M., et al. 2016, MNRAS, 462, 3955

  150. [158]

    , 2023, , 521, 129

    Pérez-Millán, D. , 2023, , 521, 129

  151. [159]

    2013, MNRAS, 433, 1505

    del Pino, Andrés, . 2013, MNRAS, 433, 1505

  152. [160]

    Rey, S.-C.., Kim, S., Chung, J., Lee, Y., 2023, , 945, 140

  153. [161]

    S., Terndrup, D

    Reyden, B. S., Terndrup, D. M., Pogge, R.W., Lauer, T. R. 1999, , 517, 650

  154. [162]

    2021, , tmp9,

    Riffel, R. . 2021, , tmp9,

  155. [163]

    , 2011, , 739, L49

    Rodighiero, G. , 2011, , 739, L49

  156. [164]

    K., Cooper, M

    Rodriguez Wimberly, M. K., Cooper, M. C., Fillingham, S. P., Boylan-Kolchin, M., Bullock, J. S., Garrison-Kimmel, S, 2019, , 483, 403

  157. [165]

    , 2023, , 522, 130

    Romero-Gómez, J. , 2023, , 522, 130

  158. [166]

    , 2024a, , 527, 9715

    Romero-Gómez, J. , 2024a, , 527, 9715

  159. [167]

    , 2024b, , 689, 40

    Romero-Gómez, J. , 2024b, , 689, 40

  160. [168]

    Rusakov, V., , 2021, , 502, 6

  161. [169]

    , 2007, , 173, 267

    Salim, S. , 2007, , 173, 267

  162. [170]

    , 2012, , 420, 20

    Salucci, P. , 2012, , 420, 20

  163. [171]

    S\' a nchcez-BL\' a zquez, P., , 2009, , 499, 47

  164. [172]

    Sandage, A., Bibggeli, B., 1984, , 89, 919

  165. [173]

    A., , 2016, , 829, 863

    Santana, F. A., , 2016, , 829, 863

  166. [174]

    2015, , 583, 126

    Savino, A., Salaris, M., Tolstoy, E. 2015, , 583, 126

  167. [175]

    Savino, A., Tolstoy, E., Salaris, M., Monelli, M., de Boer, T. J. L., 2019, , 630, 116

  168. [176]

    Salvadori, S., Ferrara, A., Schneider, R., 2008, , 386, 348

  169. [177]

    B., 2022,

    Seo, M., Ann, H. B., 2022, . 514, 5853

  170. [178]

    B., 2023, , 520, 5521

    Seo, M., Ann, H. B., 2023, , 520, 5521

  171. [179]

    L., 1968, Atlas de Galaxias Australes (Cordoba: Observatorio Astronomico)

    S\' e rsic, J. L., 1968, Atlas de Galaxias Australes (Cordoba: Observatorio Astronomico)

  172. [180]

    P., Davis, M

    Schlegel, D., Finkbeiner, D. P., Davis, M. 1998, , 500, 525

  173. [181]

    Seo, Mira, Ann, H. B. 2023, , 520, 5521

  174. [182]

    R., Iliev, I

    Shapiro, P. R., Iliev, I. T., Raga, A. C., 2004, , 348, 753

  175. [183]

    Simien, F., & Prugniel, P., 2002, A&A, 384, 371

  176. [184]

    D., , 2017, , 837, 102

    Skillman E. D., , 2017, , 837, 102

  177. [185]

    N., Small, I., Mobasher, B., Stott, J., Nisbet, D., 2014, , 437, 3516

    Sobral, D., Best, P. N., Small, I., Mobasher, B., Stott, J., Nisbet, D., 2014, , 437, 3516

  178. [186]

    Smith, R., Fellhauer, M., Assmann, P., 2012, , 420, 1990

  179. [187]

    S., Steinhardt, C

    Speagle, J. S., Steinhardt, C. I., Capak, P. L., Silverman, J. D., 2014, , 437, 3516

  180. [188]

    Spitzer L., Jr., Baade W., 1951, ApJ, 113, 413

  181. [189]

    Strateva, I., , 2001, , 122, 1861

  182. [190]

    Steyrleithner, P., Hensler, G., Boselli, A., 2020, , 494, 1114

  183. [191]

    Y., Kravtsov, A

    Tassis, K., Gnedin, N. Y., Kravtsov, A. V., 2012, , 745, 68

  184. [192]

    2015, ApJ, 799, 172

    Toloba, E., Guhathakurta, P., Boselli, A., et al. 2015, ApJ, 799, 172

  185. [193]

    Tolstoy, E., Hill, V., Tosi, M., 2009, ARA&A, 47, 371

  186. [194]

    Tosi, M., 2003, Astrophysics and Space Science, 284, 65

  187. [195]

    B., Trentham, N., 2008, , 135, 1488 Tosi, M., 2003, Astrophysics and Space Science, 284, 65

    Tully, R. B., Trentham, N., 2008, , 135, 1488 Tosi, M., 2003, Astrophysics and Space Science, 284, 65

  188. [196]

    , 2017, , 606, 135

    Urich, L. , 2017, , 606, 135

  189. [197]

    P., 1986, , 305, 889

    Vader, J. P., 1986, , 305, 889

  190. [198]

    van den Bergh, S., 1976, , 206, 883

  191. [199]

    1994, , 428, 617

    van den Bergh, S. 1994, , 428, 617

  192. [200]

    D., Haynes, M

    van Zee, L., Skillman, E. D., Haynes, M. P., 2004, , 128, 121

  193. [201]

    P., 1984, , 139, L9

    Vigroux, L., Souviron, J., Vader, J. P., 1984, , 139, L9

  194. [202]

    P., Savage, B

    Wakker, B. P., Savage, B. D., 2009, , 182, 378

  195. [203]

    G., Mateo, M., Olszewski, E

    Walker, M. G., Mateo, M., Olszewski, E. W., Penarruria, J., Evans, N. W., Gilmore, G. 2009, 704, 127

  196. [204]

    Wang, B., 2022, , 516, 429

  197. [205]

    Websterm D., Frebel, A., Bland-Hawthorn, J., 2016, , 818, 80

  198. [206]

    R., 2011, , 739, 5

    Weisz, D. R., 2011, , 739, 5

  199. [207]

    R., Dolphin, A

    Weisz, D. R., Dolphin, A. E., Skillman, E. D., Holtzman, J., Gilbert, K. M., Dalcanton, J. J., Williams, B. F., 2014, , 789, 147

  200. [208]

    R., Dolphin, A

    Weisz, D. R., Dolphin, A. E., Skillman, E. D., Holtzman, J., Gilbert, K. M., Dalcanton, J. J., Williams, B. F., 2015, , 804, 136

  201. [209]

    R., , 2019, , 885, L8

    Weisz, D. R., , 2019, , 885, L8

  202. [210]

    B., Bullock, J

    Wheeler, C., Pace, A. B., Bullock, J. S. . 2017, , 465, 24207

  203. [211]

    H., Turk, M

    Wise, J. H., Turk, M. J., Norman, M. L., Abel, T., 2012, ApJ, 745, 50

  204. [212]

    M., Prochaska, J

    Wolfe, A. M., Prochaska, J. X., 1998, ApJ, 494, L15

  205. [213]

    C., Brooks, A

    Wright, A. C., Brooks, A. M., Weisz, D. R., Christensen, C. R., 2019, , 482, 1176

  206. [214]

    G., et al

    York, D. G., et al. 2000, AJ, 120, 1579

  207. [215]

    J., Li, C., Boquien, M., Rossi, G., 2020, , 497,47

    Zhou, S., Mo, H. J., Li, C., Boquien, M., Rossi, G., 2020, , 497,47

Pith tools

Reviewed August 6, 2026 · model on record in the stance chip above.