Another look at the size of the low‐surface‐brightness galaxy VCC 1661 in the Virgo Cluster

Koch, Andreas; Black, Christine S.; Rich, R. Michael; Longstaff, Francis A.; Collins, Michelle L. M.

doi:10.1002/asna.201613274

Cited by 4 publications

(4 citation statements)

References 44 publications

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“…Findings of dwarf galaxies with extreme LSB have been reported two decades ago (e.g., Impey et al 1988;Bothun et al 1991). UDGs were detected in the Coma cluster using deep low-resolution imaging data obtained with small telescopes (van Dokkum et al 2015a), and more UDGs were found in nearby galaxy clusters since then (Koda et al 2015;Mihos et al 2015;Muñoz et al 2015;van der Burg et al 2016;Koch et al 2017;Román & Trujillo 2017a). Differing from the classical LSB galaxies that usually have a central surface brightness down to µ(B, 0) ∼ 22 − 23 mag arcsec −2 (Impey & Bothun 1997;Impey et al 2001;Ceccarelli et al 2012;Geller et al 2012), UDGs have a much lower central surface brightness (µ(g, 0) = 24 − 26 mag arcsec −2 ), but their half-light radius r e > 1.5 kpc is comparable to that of typical L * galaxies, and their stellar mass (<∼ 10 8 M ⊙ ) is two orders of magnitude lower (van Dokkum et al 2015a).…”

Section: Introductionmentioning

confidence: 92%

Deep Imaging of the HCG 95 Field. I. Ultra-diffuse Galaxies

Shi

Zheng

Zhao

et al. 2017

ApJ

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We present a detection of 89 candidates of ultra-diffuse galaxies (UDGs) in a 4.9 degree 2 field centered on the Hickson Compact Group 95 (HCG 95) using deep g-and r-band images taken with the Chinese Near Object Survey Telescope. This field contains one rich galaxy cluster (Abell 2588 at z=0.199) and two poor clusters (Pegasus I at z=0.013 and Pegasus II at z=0.040). The 89 candidates are likely associated with the two poor clusters, giving about 50 − 60 true UDGs with a half-light radius r e > 1.5 kpc and a central surface brightness µ(g, 0) > 24.0 mag arcsec −2 . Deep z ′ -band images are available for 84 of the 89 galaxies from the Dark Energy Camera Legacy Survey (DECaLS), confirming that these galaxies have an extremely low central surface brightness. Moreover, our UDG candidates are spread over a wide range in g − r color, and ∼26% are as blue as normal star-forming galaxies, which is suggestive of young UDGs that are still in formation. Interestingly, we find that one UDG linked with HCG 95 is a gas-rich galaxy with H I mass 1.1×10 9 M ⊙ detected by the Very Large Array, and has a stellar mass of M ⋆ ∼ 1.8 × 10 8 M ⊙ . This indicates that UDGs at least partially overlap with the population of nearly dark galaxies found in deep H I surveys. Our results show that the high abundance of blue UDGs in the HCG 95 field is favored by the environment of poor galaxy clusters residing in H I-rich large-scale structures.

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Section: Introductionmentioning

confidence: 92%

Deep Imaging of the HCG 95 Field. I. Ultra-diffuse Galaxies

Shi

Zheng

Zhao

et al. 2017

ApJ

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“…Apart from some exceptions, there is a visible trend that as galaxies become redder they also become smaller. VCC1661 is the galaxy with the largest effective radius (for a detailed study of this extended galaxy see Koch et al 2017).…”

Section: Reasons For the Scatter In Cmrmentioning

confidence: 99%

Young stellar populations in early-type dwarf galaxies

Hamraz

Peletier

Khosroshahi

et al. 2019

A&A

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Aims. To understand the stellar population content of early-type dwarf galaxies (dEs) and their environmental dependence, we compare the slopes and intrinsic scatter of color–magnitude relations (CMRs) for three nearby clusters, Fornax, Virgo, and Coma. Additionally, we present and compare internal color profiles of these galaxies to identify central blue regions with younger stars. Methods. We use the imaging of the HST/ACS Fornax cluster in the magnitude range of −18.7 ≤ Mg′ ≤ −16.0 to derive magnitudes, colors, and color profiles, which we compare with literature measurements from the HST/ACS Virgo and Coma Cluster Survey. We take advantage of HST accuracy to investigate and parameterize the (g′−z′) color profiles of these dEs. Results. Based on analysis of the color profiles, we report on a large number of dEs with young stellar populations at their center in all three clusters. While for Virgo and Coma the number of blue-cored dEs is found to be 85%±2% and 53%±3%, respectively, for Fornax, we find that all galaxies have a blue core. We show that bluer cores reside in fainter dEs, similar to the trend seen in nucleated dEs. We find no correlation between the luminosity of the galaxy and the size of its blue core. Moreover, a comparison of the CMRs of the three clusters shows that the scatter in the CMR of Virgo is considerably larger than in the Fornax and Coma clusters. Presenting adaptive smoothing we show that the galaxies on the blue side of the CMR often show evidence for dust extinction, which strengthens the interpretation that the bluer colors are due to young stellar populations. We also find that outliers on the red side of the CMR are more compact than what is expected for their luminosity. We find several of these red outliers in Virgo, often close to more massive galaxies. No red outlying compact early-types are found in Fornax and Coma in this magnitude range while we find three in the Virgo cluster. We show that the CMR of the Fornax and Virgo clusters are slightly bluer than that of Coma. We suggest that the large number of outliers and larger scatter found for Virgo CMR are a result of the alternative assembly history of this cluster.

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“…The images used in this work were taken as part of the HERON survey, and details of their reduction are given in Rich et al (2019) alongside a general characterization of the galaxies, for instance in terms of their halo sizes. Imaging for the two targets was acquired in October and November 2011 with the 28-inch Centurion (C28) telescope at the Polaris Observatory Association in Lockwood Valley, California (Rich et al 2012(Rich et al , 2019Brosch et al 2015;Koch et al 2017). The pixel scale of the detector is 0.82 pixel −1 , which for NGC 720 has been resampled by a factor of two in either dimension.…”

Section: Observations: Centurion 28 Imagingmentioning

confidence: 99%

“…However, at its absolute magnitude, this merging candidate appears too large by a factor of a few, when compared to typical galaxies of similar magnitude. Its corresponding half-light radius is 2.4 ± 0.3 kpc, and an investigation of systematically more extended objects is often used to confirm the presence and absence of tidal disruptions (Koch et al 2017). Indeed, the contender within NGC 2768 lies within ±1.5 mag of the strongly disrupted NGC 4449B (Rich et al 2012) and HCC-087 (Koch et al 2012) at similarly large radii.…”

Section: Pelops In Contextmentioning

confidence: 99%

The Halos and Environments of Nearby Galaxies (HERON) survey

Koch-Hansen,

Pasquali,

Michael Rich

et al. 2024

A&A

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The shapes of galaxies, their outer regions in particular, are important guideposts to their formation and evolution. In this work, we report on the discovery of strongly box-shaped morphologies of the otherwise well-studied elliptical and lenticular galaxies NGC 720 and NGC 2768 from deep imaging. The boxiness is strongly manifested in the parameter shape $A_4/a$ of $-0.04$ in both objects, and significant center shifts of the isophotes of sim 2--4 kpc are also seen. One reason for such asymmetries commonly stated in the literature is a merger origin, although the number of such cases is still sparse, and the exact properties of the individual boxy objects are highly diverse. Indeed, for NGC 2768, we identify a progenitor candidate (dubbed "Pelops") in the residual images, which appears to be a dwarf satellite that is currently merging with NGC 2768. At its absolute magnitude of M$_r$ of $-$12.2 mag, the corresponding Sersic radius of 2.4 kpc is more extended than those of typical dwarf galaxies from the literature. However, systematically larger radii are known to occur in systems that are in tidal disruption. This finding is bolstered by the presence of a tentative tidal stream feature on archival GALEX data. Finally, further structures in the fascinating host galaxy include rich dust lanes and a vestigial X-shaped bulge component.

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Another look at the size of the low‐surface‐brightness galaxy VCC 1661 in the Virgo Cluster

Cited by 4 publications

References 44 publications

Deep Imaging of the HCG 95 Field. I. Ultra-diffuse Galaxies

Deep Imaging of the HCG 95 Field. I. Ultra-diffuse Galaxies

Young stellar populations in early-type dwarf galaxies

The Halos and Environments of Nearby Galaxies (HERON) survey

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