A rare example of low surface-brightness radio lobes in a gas-rich early-type galaxy: the story of NGC 3998

In this paper, we report the discovery of 27 low-surface brightness galaxies, of which 12 are candidates for ultra-diffuse galaxies (UDG) in the Hydra I cluster, based on deep observations taken as part of the VST Early-type Galaxy Survey (VEGAS). This first sample of UDG candidates in the Hydra I cluster represents an important step in our project that aims to enlarge the number of confirmed UDGs and, through study of statistically relevant samples, constrain the nature and formation of UDGs. This study presents the main properties of this class of galaxies in the Hydra I cluster. For all UDGs, we analysed the light and colour distribution, and we provide a census of the globular cluster (GC) systems around them. Given the limitations of a reliable GC selection based on two relatively close optical bands only, we find that half of the UDG candidates have a total GC population consistent with zero. Of the other half, two galaxies have a total population larger than zero at 2σ level. We estimate the stellar mass, the total number of GCs, and the GC specific frequency (SN). Most of the candidates span a range of stellar masses of 107 − 108 M⊙. Based on the GC population of these newly discovered UDGs, we conclude that most of these galaxies have a standard or low dark matter content, with a halo mass of ≤1010 M⊙.

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A tidal tale: detection of several stellar streams in the environment of NGC 1052

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935463 ◽

2019 ◽

Vol 624 ◽

pp. L6 ◽

Cited By ~ 17

Author(s):

Oliver Müller ◽

R. Michael Rich ◽

Javier Román ◽

Mustafa K. Yıldız ◽

Michal Bílek ◽

...

Keyword(s):

Dark Matter ◽

Galaxy Formation ◽

Surface Brightness ◽

Dwarf Galaxy ◽

Early Type ◽

Tidal Interaction ◽

Low Surface Brightness ◽

Stellar Streams ◽

Early Type Galaxy ◽

Band Image

The possible existence of two dark-matter-free galaxies (NGC 1052-DF2 and NGC 1052-DF4) in the field of the early-type galaxy NGC 1052 presents a challenge to theories of dwarf galaxy formation according to the current cosmological paradigm. We carried out a search for signatures of past interactions connected to the putative hosts of NGC 1052-DF2 and NGC 1052-DF4 using a very deep L-band image obtained with the 0.7 m Jeanne Rich telescope that reach a surface brightness limit of 28.5 mag arcsec−2 in the r band. We found several low-surface brightness features, possibly consistent with an ongoing merger history in this group. We find a tidal interaction between NGC 1052 and NGC 1047, confirming a physical association. Furthermore, we find a stellar loop around NGC 1052 in the direction of NGC 1042 and a stellar stream pointing in the direction of NGC 1052-DF2, but they are not directly connected. We find no evidence for a recent tidal interaction for NGC 1052-DF2 and NGC 1052-DF4. No LSB features have been uncovered around the spiral galaxy NGC 1042, which leaves the association (physical or projected) between NGC 1052 and NGC 1042 ambiguous, although they have similar radial velocities. Their association will only be established when accurate distances to both objects have been measured.

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Applying galactic archeology to massive galaxies using deep imaging surveys

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315003518 ◽

2014 ◽

Vol 10 (S311) ◽

pp. 120-125

Author(s):

Pierre-Alain Duc

Keyword(s):

Galaxy Evolution ◽

Surface Brightness ◽

Local Group ◽

Diffuse Light ◽

Early Type ◽

Massive Galaxies ◽

Systematic Survey ◽

Deep Imaging ◽

Low Surface Brightness ◽

Optical Surveys

AbstractVarious programs aimed at exploring the still largely unknown low surface brightness Universe with deep imaging optical surveys have recently started. They open a new window for studies of galaxy evolution, pushing the technique of galactic archeology outside the Local Group (LG). The method, based on the detection and analysis of the diffuse light emitted by collisional debris or extended stellar halos (rather than on stellar counts as done for LG systems), faces however a number of technical difficulties, like the contamination of the images by reflection halos and Galactic cirrus. I review here the on-going efforts to address them and highlight the preliminary promising results obtained with a systematic survey with MegaCam on the CFHT of nearby massive early-type galaxies done as part of the ATLAS3D, NGVS and MATLAS collaborations.

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Census and classification of low-surface-brightness structures in nearby early-type galaxies from the MATLAS survey

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2248 ◽

2020 ◽

Vol 498 (2) ◽

pp. 2138-2166

Author(s):

Michal Bílek ◽

Pierre-Alain Duc ◽

Jean-Charles Cuillandre ◽

Stephen Gwyn ◽

Michele Cappellari ◽

...

Keyword(s):

Galaxy Evolution ◽

Surface Brightness ◽

Host Galaxy ◽

Early Type ◽

Limited Sample ◽

Visual Classification ◽

Star Forming ◽

Low Surface Brightness ◽

Model Predictions

ABSTRACT The morphology of galaxies gives essential constraints on the models of galaxy evolution. The morphology of the features in the low-surface-brightness (LSB) regions of galaxies has not been fully explored yet because of observational difficulties. Here we present the results of our visual inspections of very deep images of a large volume-limited sample of 177 nearby massive early-type galaxies from the MATLAS survey. The images reach a surface-brightness limit of 28.5–29 mag arcsec−2 in the g′ band. Using a dedicated navigation tool and questionnaire, we looked for structures at the outskirts of the galaxies such as tidal shells, streams, tails, disturbed outer isophotes, or peripheral star-forming discs, and simultaneously noted the presence of contaminating sources, such as Galactic cirrus. We also inspected internal substructures such as bars and dust lanes. We discuss the reliability of this visual classification investigating the variety of answers made by the participants. We present the incidence of these structures and the trends of the incidence with the mass of the host galaxy and the density of its environment. We find an incidence of shells, stream, and tails of approximately 15 per cent, about the same for each category. For galaxies with masses over 1011 M⊙, the incidence of shells and streams increases about 1.7 times. We also note a strong unexpected anticorrelation of the incidence of Galactic cirrus with the environment density of the target galaxy. Correlations with other properties of the galaxies, and comparisons to model predictions, will be presented in future papers.

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The LOFAR view of FR 0 radio galaxies

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038671 ◽

2020 ◽

Vol 642 ◽

pp. A107

Author(s):

A. Capetti ◽

M. Brienza ◽

R. D. Baldi ◽

G. Giovannini ◽

R. Morganti ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Surface Brightness ◽

Low Frequency ◽

Galactic Nuclei ◽

Early Type ◽

Resolution Limit ◽

Low Surface Brightness ◽

Continuous Population ◽

Extended Emission ◽

Radio Power

We explore the low-frequency radio properties of the sources in the Fanaroff-Riley class 0 catalog (FR0CAT) as seen by the Low-Frequency ARray (LOFAR) observations at 150 MHz. This sample includes 104 compact radio active galactic nuclei (AGN) associated with nearby (z < 0.05) massive early-type galaxies. Sixty-six FR0CAT sources are in the sky regions observed by LOFAR and all of them are detected, usually showing point-like structures with sizes of ≲3–6 kpc. However, 12 FR 0s present resolved emission of low surface brightness, which contributes between 5% and 40% of the total radio power at 150 MHz, usually with a jetted morphology extending between 15 and 50 kpc. No extended emission is detected around the other FR 0s, with a typical luminosity limit of ≲5 × 1022 W Hz−1 over an area of 100 kpc × 100 kpc. The spectral slopes of FR 0s between 150 MHz and 1.4 GHz span a broad range (−0.7 ≲ α ≲ 0.8) with a median value of ᾱ ∼ 0.1; 20% of them have a steep spectrum (α ≳ 0.5), which is an indication of the presence of substantial extended emission confined within the spatial resolution limit. The fraction of FR 0s showing evidence for the presence of jets, by including both spectral and morphological information, is at least ∼40%. This study confirms that FR 0s and FR Is can be interpreted as two extremes of a continuous population of jetted sources, with the FR 0s representing the low end in size and radio power.

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Early-type galaxy distances from the Fundamental Plane and surface brightness fluctuations

Monthly Notices of the Royal Astronomical Society ◽

10.1046/j.1365-8711.2002.05080.x ◽

2002 ◽

Vol 330 (2) ◽

pp. 443-457 ◽

Cited By ~ 57

Author(s):

John P. Blakeslee ◽

John R. Lucey ◽

John L. Tonry ◽

Michael J. Hudson ◽

Vijay K. Narayanan ◽

...

Keyword(s):

Surface Brightness ◽

Early Type ◽

Fundamental Plane ◽

Surface Brightness Fluctuations ◽

Early Type Galaxy

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Chandra Early-Type Galaxy Atlas

Proceedings of the International Astronomical Union ◽

10.1017/s174392131800594x ◽

2018 ◽

Vol 14 (S342) ◽

pp. 242-243

Author(s):

Dong-Woo Kim ◽

Craig Anderson ◽

Douglas Burke ◽

Raffaele D’Abrusco ◽

Giuseppina Fabbiano ◽

...

Keyword(s):

Surface Brightness ◽

Structural Features ◽

Early Type ◽

Evolutionary Mechanisms ◽

Hot Gas ◽

Spatially Resolved ◽

Data Products ◽

Formation And Evolution ◽

High Level ◽

Early Type Galaxy

AbstractThe hot ISM in early-type galaxies (ETGs) plays a crucial role in understanding their formation and evolution. The structural features of the hot gas identified by Chandra observations point to key evolutionary mechanisms, (e.g., kim12). In our Chandra Galaxy Atlas (CGA) project, taking full advantage of the Chandra capabilities, we systematically analyzed the archival Chandra data of 72 ETGs and produced uniform data products of the hot gas properties. The main data products include spatially resolved 2D spectral maps of the hot gas from individual galaxies. We emphasize that new features can be identified in the spectral maps which are not easily visible in the surface brightness maps. The high-level images can be viewed at the dedicated CGA website, and the CGA data products can be downloaded to compare with other wavelength data and to perform user-specific analyses. Utilizing our data products, we will further address focused science topics.

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The Frequency of Anomalously Red Galaxies in SDSS Clusters

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2014.34 ◽

2014 ◽

Vol 31 ◽

Author(s):

O. Shearman ◽

K. A. Pimbblet

Keyword(s):

Surface Brightness ◽

Dust Content ◽

Early Type ◽

Late Type ◽

Cluster Membership ◽

Cluster Galaxies ◽

Low Surface Brightness ◽

Magnitude Diagram ◽

Red Galaxies ◽

Red Sequence

AbstractWe present a systematic photometric search for spectroscopically confirmed anomalously red galaxies members of 748 low redshift clusters between 0.03 z 0.17 from the SDSS-C4 cluster catalogue (Miller et al. 2005). For each cluster we spectroscopically determine cluster membership, construct a colour-magnitude diagram and fit the red sequence using a robust bi-weight fit. We define an “anomalously red galaxy” as having a (g - r) colour of greater than 3σ redward of the fitted cluster colour-magnitude relation. We find that of 7485 galaxies at r ≤ 17.77 in (g - r), 7 galaxies are anomalously red – 0.0935 per cent of all galaxies in our sample. We show that two of the red outliers are caused by red contamination from nearby sources and are therefore not intrinsically anomalous red. However, 5 have no underlying cause to be so red and we speculate that they may have a high internal dust content. These intrinsically red galaxies are rare – comprising no more than 0.0668 per cent of all cluster galaxies. Most are morphologically early type galaxies, with a few probable late type galaxies that are viewed edge-on and one low surface brightness late type. One of our anomalously red galaxies appears to be a dust-shrouded starburst and we speculate that this may be a unique galaxy amoungst this galaxy set.

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VEGAS: a VST Early-type GAlaxy Survey

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936435 ◽

2020 ◽

Vol 635 ◽

pp. A3 ◽

Cited By ~ 5

Author(s):

Enrichetta Iodice ◽

Marilena Spavone ◽

Arianna Cattapan ◽

Elena Bannikova ◽

Duncan A. Forbes ◽

...

Keyword(s):

Surface Brightness ◽

Major Axis ◽

Integration Time ◽

High Angular Resolution ◽

Evolutionary Stage ◽

Wide Field ◽

Early Type ◽

Semi Major Axis ◽

Galaxy Groups ◽

Early Type Galaxy

Context. This paper is based on the multi-band VST Early-type GAlaxy Survey (VEGAS) with the VLT Survey Telescope (VST). We present new deep photometry of the IC 1459 group in g and r band. Aims. The main goal of this work is to investigate the photometric properties of the IC 1459 group, and to compare our results with those obtained for other galaxy groups studied in VEGAS, in order to provide an initial view of the variation of their properties as a function of the evolution of the system. Methods. For all galaxies in the IC 1459 group, we fit isophotes and extract the azimuthally averaged surface-brightness profiles, the position angle, and ellipticity profiles as a function of the semi-major axis. We also extract the average colour profile. In each band, we estimate the total magnitude, effective radius, mean colour, and total stellar mass for each galaxy in the group. We then look at the structure of the brightest galaxies and the faint features in their outskirts, considering also the intragroup component. Results. The wide field of view, long integration time, high angular resolution, and arcsec-level seeing of OmegaCAM at VST allow us to map the light distribution of IC 1459 down to a surface brightness level of 29.26 mag arcsec−2 in g band and 28.85 mag arcsec−2 in r band, and out to 7−10Re, and to detect the optical counterpart of HI gas around IC 1459. We also carry out an in-depth exploration of three low-density environments and provide information to understand how galaxy and group properties change with the group evolution stage. Conclusions. Good agreement is found between our results and predictions of numerical simulations regarding the structural properties of the brightest galaxies of the groups. We suggest that the structure of the outer envelope of he brightest cluster galaxies (i.e. the signatures of past mergers and tidal interactions), the intra-group light, and the HI amount and distribution may be used as indicators of the evolutionary stage and mass assembly of galaxy groups.

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