- ID:
- ivo://CDS.VizieR/J/A+A/463/503
- Title:
- Early-type dwarf galaxies in Fornax cluster
- Short Name:
- J/A+A/463/503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the photometric properties of the early-type Fornax cluster dwarf galaxy population, based on a wide field imaging study of the central cluster area in V and I. We used the instrument/telescope combination IMACS/Magellan at Las Campanas Observatory. We create a fiducial sample of Fornax cluster dwarf ellipticals (dEs) in the following three steps: (1) To verify cluster membership, we measured I-band surface brightness fluctuation (SBF) distances to candidate dEs; (2) We re-assessed morphological classifications for candidate dEs too faint for SBF detection; and (3) We searched for new candidate dEs in the size-luminosity regime close to the resolution limit of previous surveys. (1) We confirm cluster membership for 28 candidate dEs in the range -16.6<M_V_<-10.1mag by means of SBF distances. We find no SBF background galaxy. (2) Of 51 further candidate dEs in the range -13.2<M_V_<-8.6mag, 2/3 are confirmed as probable cluster members by morphological re-assessment, while 1/3 are re-classified as probable background objects. (3) We find 12 new dE candidates in the range -12.3<M_V_<-8.8mag. The surface brightness-magnitude relation defined by the resulting fiducial dE sample shows that Fornax dEs are about 40% larger than Local Group dEs. The Fornax dE sample furthermore defines a colour-magnitude relation that appears slightly shallower than that of Local Group dEs. The early-type dwarf galaxy luminosity function in Fornax has a faint end slope alpha=-1.1+/- 0.1.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/128/1990
- Title:
- Early-type field galaxies at z~0.75
- Short Name:
- J/AJ/128/1990
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the luminosity function of morphologically selected E/S0 galaxies from z=0.5 to 1.0 using deep high-resolution Advanced Camera for Surveys (ACS) imaging data. Our analysis covers an area of 48arcmin^2^ (8 times the area of the Hubble Deep Field North) and extends 2mag deeper (I~24 mag) than was possible in the Deep Groth Strip Survey (DGSS). Our fields were observed as part of the ACS Guaranteed Time Observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/818/182
- Title:
- Early-type galaxies at z<0.04 star formation rates
- Short Name:
- J/ApJ/818/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We address the relation between star formation and active galactic nucleus (AGN) activity in a sample of 231 nearby (0.0002<z<0.0358) early-type galaxies by carrying out a multi-wavelength study using archival observations in the UV, IR, and radio. Our results indicate that early-type galaxies in the current epoch are rarely powerful AGNs, with P<10^22^W/Hz for a majority of the galaxies. Only massive galaxies are capable of hosting powerful radio sources while less massive galaxies are hosts to lower radio power sources. Evidence of ongoing star formation is seen in approximately 7% of the sample. The star formation rate (SFR) of these galaxies is less than 0.1M_{sun}_/yr. They also tend to be radio faint (P<10^22^W/Hz). There is a nearly equal fraction of star-forming galaxies in radio faint (P<10^22^W/Hz) and radio bright galaxies (P>=10^22^W/Hz) suggesting that both star formation and radio mode feedback are constrained to be very low in our sample. We notice that our galaxy sample and the Brightest Cluster Galaxies follow similar trends in radio power versus SFR. This may be produced if both radio power and SFR are related to stellar mass.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2484
- Title:
- Early-type galaxies color evolution
- Short Name:
- J/AJ/127/2484
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the color evolution of elliptical and S0 galaxies in six clusters of galaxies inside the redshift range 0.78<z<1.27. For each cluster, we used imaging from the Hubble Space Telescope (HST) to determine morphological types of the galaxies. These types were determined both by an automated technique and from visual inspection. We performed simulations to determine the accuracy of the automated classifications and found a success rate of ~75% at m(L*) or brighter magnitudes for most of our HST imaging data with the fraction of late-type galaxies identified as early-type galaxies to be ~10% at m(L*) to ~20% at m(L*+2). From ground-based optical and near-infrared imaging, we measured the zero point and scatter in the color-magnitude relation of the elliptical and S0 galaxy populations, which we combine with the sample of Stanford et al. (1998ApJ...492..461S), yielding a sample of cluster early-type galaxies that span a look-back time of almost 9Gyr from the present.
- ID:
- ivo://CDS.VizieR/J/A+A/636/A8
- Title:
- Early type galaxies g-r colour fits maps
- Short Name:
- J/A+A/636/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of neutral hydrogen (HI) and molecular gas show that 50% of all nearby early-type galaxies (ETGs) contain some cold gas. Molecular gas is always found in small gas discs in the central region of the galaxy, while neutral hydrogen is often distributed in a low-column density disc or ring typically extending well beyond the stellar body. Dust is frequently found in ETGs as well. The goal of our study is to understand the link between dust and cold gas in nearby ETGs as a function of HI content. We analyse deep optical g-r images obtained with the MegaCam camera at the Canada-France-Hawaii Telescope for a sample of 21 HI-rich and 41 HI-poor ETGs. We find that all HI- rich galaxies contain dust seen as absorption. Moreover, in 57 percent of these HI-rich galaxies, the dust is distributed in a large-scale spiral pattern. Although the dust detection rate is relatively high in the HI-poor galaxies (59 percent), most of these systems exhibit simpler dust morphologies without any evidence of spiral structures. We find that the HI-rich galaxies possess more complex dust morphology extending to almost two times larger radii than HI-poor objects. We measured the dust content of the galaxies from the optical colour excess and find that HI-rich galaxies contain six times more dust (in mass) than HI-poor ones. In order to maintain the dust structures in the galaxies, continuous gas accretion is needed, and the substantial HI gas reservoirs in the outer regions of ETGs can satisfy this need for a long time. We find that there is a good correspondence between the observed masses of the gas and dust, and it is also clear that dust is present in regions further than 3 Reff. Our findings indicate an essential relation between the presence of cold gas and dust in ETGs and offer a way to study the interstellar medium in more detail than what is possible with. HI observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/706/158
- Title:
- Early-type galaxies in PEARS
- Short Name:
- J/ApJ/706/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) slitless grism spectra from the PEARS program, we study the stellar populations of morphologically selected early-type galaxies in the GOODS North and South fields. The sample - extracted from a visual classification of the (v2.0) HST/ACS images and restricted to redshifts z>0.4 - comprises 228 galaxies (i_F775W_<24mag, AB) out to z<~1.3 over 320arcmin^2^, with a median redshift z_M_=0.75. This work significantly increases our previous sample from the GRAPES survey in the HUDF (18 galaxies over ~11arcmin^2^). The grism data allow us to separate the sample into "red" and "blue" spectra, with the latter comprising 15% of the total. Three different grids of models parameterizing the star formation history are used to fit the low-resolution spectra.
- ID:
- ivo://CDS.VizieR/J/A+A/496/683
- Title:
- Early-type galaxies in the Centaurus cluster
- Short Name:
- J/A+A/496/683
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the properties of the early-type dwarf galaxy population in the Centaurus cluster. We investigate the galaxy luminosity function, galaxy scaling relations down to M_V_=-10mag. On deep VLT/FORS1 V- and I-band images of the central part of the cluster, we identify cluster dwarf-galaxy candidates using both morphological and surface brightness selection criteria. The candidates' total magnitudes and central surface brightnesses are derived from the analysis of their surface brightness profiles.
- ID:
- ivo://CDS.VizieR/J/A+A/526/A72
- Title:
- Early-type galaxies in the EGS
- Short Name:
- J/A+A/526/A72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The fundamental plane links the structural properties of early-type galaxies such as its surface brightness and effective radius with its dynamics. The study of the fundamental plane evolution therefore has important implications for models of galaxy formation and evolution. This work aims to identify signs of evolution of early-type galaxies through the study of parameter correlations such as the fundamental plane, the Kormendy, and the Faber-Jackson relations, using a sample of 135 field galaxies extracted from the Extended Groth Strip in the redshift range 0.2<z<1.2.
- ID:
- ivo://CDS.VizieR/J/MNRAS/406/382
- Title:
- Early-type galaxies in the SDSS Stripe82
- Short Name:
- J/MNRAS/406/382
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the properties of "peculiar" early-type galaxies (ETGs) in the local Universe that show (faint) morphological signatures of recent interactions such as tidal tails, shells and dust lanes. Standard-depth (~51s exposure) multicolour galaxy images from the Sloan Digital Sky Survey (SDSS) are combined with the significantly (~2mag) deeper monochromatic images from the public SDSS Stripe82 (-50{deg}<{alpha}<59{deg}, -1.25{deg}<{delta}<1.25{deg}) to extract, through careful visual inspection, a robust sample of nearby (z<0.05), luminous (M_r_<-20.5) ETGs, including a subset of ~70 peculiar systems. ~18% of ETGs exhibit signs of disturbed morphologies (e.g. shells), while ~7% show evidence of dust lanes and patches. An analysis of optical emission-line ratios indicates that the fraction of peculiar ETGs that are Seyferts or LINERs (19.4%) is twice the corresponding values in their relaxed counterparts (10.1%). LINER-like emission is the dominant type of nebular activity in all ETG classes, plausibly driven by stellar photoionization associated with recent star formation. An analysis of ultraviolet-optical colours indicates that, regardless of the luminosity range being considered, the fraction of peculiar ETGs that have experienced star formation in the last Gyr is a factor of ~1.5 higher than that in their relaxed counterparts. The spectrophotometric results strongly suggest that the interactions that produce the morphological peculiarities also induce low-level recent star formation which, based on the recent literature, are likely to contribute a few per cent of the stellar mass over the last ~1Gyr. Peculiar ETGs preferentially inhabit low-density environments (outskirts of clusters, groups or the field), either due to high peculiar velocities in clusters making merging unlikely or because shell systems are disrupted through frequent interactions within a cluster crossing time.
- ID:
- ivo://CDS.VizieR/J/A+A/330/423
- Title:
- Early-type galaxies kinematics
- Short Name:
- J/A+A/330/423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present data on the stellar kinematics of the brightest ellipticals in HCG 62, HCG 68, NGC 2300 groups. Moreover, we report on ASCA GIS as well as optical observations of the early-type member of the pair K 416 (NGC 5480/5481) similar, in many respects, to the dominant pair in the NGC 2300 group. The kinematics of HCG 62a/b and HCG 68a/b indicate that they are not interacting pairs. HCG 62a is instead possibly interacting with HCG 62c, as suggested by their morphology (see Mendes de Oliveira and Hickson 1994), In contrast to the results for the NGC 2300/2276 group, ASCA observations indicate a significant absence of hot gas in the K 416 system. Whether the NGC 2300 multiplet is viewed as a loose group or as a massive E+S pair, it is clear that similar morphological entities do not always show similar X-ray properties. Under the hypothesis that diffuse X-ray emission marks the group potential, we consider the possibility that K 416 is an unbound encounter. In this scenario, morphological distortions are indicative of the ongoing interaction, but are only circumstantially correlated with the physical reality of a pair/multiplet as a bound system.
