Spectroscopy of Ultra-diffuse Galaxies in the Coma Cluster

Kadowaki, Jennifer; Zaritsky, Dennis; Donnerstein, Richard L.

doi:10.3847/2041-8213/aa653d

Cited by 71 publications

(107 citation statements)

References 16 publications

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“…We also analyze all archival HST/ACS images of UDGs in Coma. Kadowaki et al 2017), and our redshifts confirm that Dragonfly 44, DFX1, and Dragonfly 42 are all members of the Coma cluster. …”

Section: Introductionsupporting

confidence: 66%

Extensive Globular Cluster Systems Associated with Ultra Diffuse Galaxies in the Coma Cluster

Dokkum

Abraham

Romanowsky

et al. 2017

ApJL

138

126

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We present Hubble Space Telescope (HST) imaging of two ultra diffuse galaxies (UDGs) with measured stellar velocity dispersions in the Coma cluster. The galaxies, Dragonfly 44 and DFX1, have effective radii of 4.7 kpc and 3.5 kpc and velocity dispersions of 47 6 8 -+ km s −1 and 30 7 7 -+ km s −1 , respectively. Both galaxies are associated with a striking number of compact objects, tentatively identified as globular clusters: N 74 18 gc =  for Dragonfly 44 and N 62 17 gc =  for DFX1. The number of globular clusters is much higher than expected from the luminosities of the galaxies but is consistent with expectations from the empirical relation between dynamical mass and globular cluster count defined by other galaxies. Combining our data with previous HST observations of Coma UDGs we find that UDGs have a factor of 6.9 2.4 1.0 -+ more globular clusters than other galaxies of the same luminosity, in contrast to a recent study of a similar sample by Amorisco et al., but consistent with earlier results for individual galaxies. The Harris et al. relation between globular cluster count and dark matter halo mass implies a median halo mass of M 1.5 10 halo 11´M for the sixteen Coma UDGs that have been observed with HST so far, with the largest and brightest having M 5 10 halo 11´M .

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Section: Introductionsupporting

confidence: 66%

Extensive Globular Cluster Systems Associated with Ultra Diffuse Galaxies in the Coma Cluster

Dokkum

Abraham

Romanowsky

et al. 2017

ApJL

138

126

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“…The derived ages and metallicities are typical for low-mass galaxies in cluster environments (e.g., van Zee et al 2004;Penny & Conselice 2008;Smith et al 2009). Kadowaki et al (2017) concluded that, on average, four Coma cluster UDGs in their sample are metal-poor by visually comparing the stacked spectrum against SSP models. The UDGs in our samples have metallicities consistent with this conclusion.…”

Section: Discussionmentioning

confidence: 99%

“…UDGs have also been found in other nearby galaxy clusters (e.g., Mihos et al 2015;Muñoz et al 2015;Martínez-Delgado et al 2016;van der Burg et al 2016;Román & Trujillo 2017), group environments (e.g., Merritt et al 2016), and the field (e.g., Bellazzini et al 2017; Leisman et al 2017). Owing to their diffuse nature, only a few UDGs have a measured spectroscopic redshift (e.g., van Dokkum et al 2015a;Kadowaki et al 2017).…”

mentioning

confidence: 99%

Low Metallicities and Old Ages for Three Ultra-diffuse Galaxies in the Coma Cluster

Conroy

Law

et al. 2018

ApJ

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A large population of ultra-diffuse galaxies (UDGs) was recently discovered in the Coma cluster. Here we present optical spectra of three such UDGs, DF7, DF44, and DF17, which have central surface brightnesses of μ g ≈24.4-25.1 mag arcsec −2 . The spectra were acquired as part of an ancillary program within the SDSS-IV MaNGA Survey. We stacked 19 fibers in the central regions from larger integral field units (IFUs) per source. With over 13.5 hr of on-source integration, we achieved a mean signal-to-noise ratio in the optical of 9.5 Å −1 , 7.9 Å −1 , and 5.0 Å −1 , respectively, for DF7, DF44, and DF17. Stellar population models applied to these spectra enable measurements of recession velocities, ages, and metallicities. respectively. Their stellar masses are (3-6)×10 8 M e . The UDGs in our sample are as old or older than galaxies at similar stellar mass or velocity dispersion (only DF 44 has an independently measured dispersion). They all follow the well-established stellar mass-stellar metallicity relation, while DF44 lies below the velocity dispersionmetallicity relation. These results, combined with the fact that UDGs are unusually large for their stellar masses, suggest that stellar mass plays a more important role in setting stellar population properties for these galaxies than either size or surface brightness.

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“…Prole et al 2019), are available for many UDGs but are of limited value in determining the properties of the stellar populations, while spectroscopy, which can provide the necessary information, is only available for a small number of galaxies (e.g. Martínez-Delgado et al 2016;Kadowaki et al 2017;Ruiz-Lara et al 2018;Ferré-Mateu et al 2018;Gu et al 2018).…”

Section: Introductionmentioning

confidence: 99%

One Hundred SMUDGes in S-PLUS: Ultra-diffuse Galaxies Flourish in the Field

Barbosa

Zaritsky

Donnerstein

et al. 2020

ApJS

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We present the first systematic study of the stellar populations of ultra-diffuse galaxies (UDGs) in the field, integrating the large area search and characterization of UDGs by the SMUDGes survey with the twelve-band optical photometry of the S-PLUS survey. Based on Bayesian modeling of the optical colors of UDGs, we determine the ages, metallicities and stellar masses of 100 UDGs distributed in an area of ∼ 330 deg 2 in the Stripe 82 region. We find that the stellar masses and metallicities of field UDGs are similar to those observed in clusters and follow the trends previously defined in studies of dwarf and giant galaxies. However, field UDGs have younger luminosityweighted ages than do UDGs in clusters. We interpret this result to mean that field UDGs have more extended star formation histories, including some that continue to form stars at low levels to the present time. Finally, we examine stellar population 2 Barbosa et al.scaling relations that show that UDGs are, as a population, similar to other low-surface brightness galaxies.

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Spectroscopy of Ultra-diffuse Galaxies in the Coma Cluster

Cited by 71 publications

References 16 publications

Extensive Globular Cluster Systems Associated with Ultra Diffuse Galaxies in the Coma Cluster

Extensive Globular Cluster Systems Associated with Ultra Diffuse Galaxies in the Coma Cluster

Low Metallicities and Old Ages for Three Ultra-diffuse Galaxies in the Coma Cluster

One Hundred SMUDGes in S-PLUS: Ultra-diffuse Galaxies Flourish in the Field

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