- ID:
- ivo://CDS.VizieR/J/AJ/131/866
- Title:
- Hot populations in M87 globular clusters
- Short Name:
- J/AJ/131/866
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To explore the production of UV-bright stars in old, metal-rich populations like those in elliptical galaxies, we have obtained Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph far- and near-UV photometry of globular clusters (GCs) in four fields in the giant elliptical (gE) galaxy M87. To a limit of m_FUV_~25 we detect a total of 66 GCs in common with the deep HST optical-band study of Kundu et al. (1999, Cat. <J/ApJ/513/733>).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/795/58
- Title:
- 1H 0323+342 rest frame optical spectrum with GHAO
- Short Name:
- J/ApJ/795/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared (NIR) imaging data of the radio-loud, narrow-line Seyfert 1 galaxy 1H 0323+342, which shows intense and variable gamma-ray activity discovered by the Fermi satellite with the Large Area Telescope. Near-infrared and optical images are used to investigate the structural properties of the host galaxy of 1H 0323+342; this together with optical spectroscopy allows us to examine its black hole mass. Based on two-dimensional (2D) multiwavelength surface-brightness modeling, we find that statistically, the best model fit is a combination of a nuclear component and a Sersic profile (n~2.8). However, the presence of a disk component (with a small bulge n~1.2) also remains a possibility and cannot be ruled out with the present data. Although at first glance a spiral-arm-like structure is revealed in our images, a 2D Fourier analysis of the imagery suggests that this structure corresponds to an asymmetric ring, likely associated with a recent violent dynamical interaction. We discuss our results in the context of relativistic jet production and galaxy evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A71
- Title:
- HRS galaxies Halpha kinematic survey
- Short Name:
- J/A+A/631/A71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new 2D high resolution Fabry-Perot spectroscopic observations of 152 star-forming galaxies which are part of the Herschel Reference Survey (HRS), a complete K-band selected, volume-limited sample of nearby galaxies, spanning a wide range in stellar mass and morphological type. Using improved data reduction techniques that provide adaptive binning based on Voronoi tessellation, using large field-of-view observations, we derive high spectral resolution (R>10,000) H{alpha} datacubes from which we compute H{alpha} maps and radial 2D velocity fields that are based on several thousand independent measurements. A robust method based on such fields allows us to accurately compute rotation curves and kinematical parameters, for which uncertainties are calculated using a method based on the power spectrum of the residual velocity fields. We check the consistency of the rotation curves by comparing our maximum rotational velocities to those derived from Hi data, and computing the i-band, NIR, stellar and baryonic Tully-Fisher relations. We use this set of kinematical data combined to those available at other frequencies to study for the first time the relation between the dynamical and the total baryonic mass (stars, atomic and molecular gas, metals and dust), and derive the baryonic and dynamical main sequence on a representative sample of the local universe.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A104
- Title:
- HRS gal. nuclear vs. integrated spectroscopy
- Short Name:
- J/A+A/615/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The determination of the relative frequency of active galactic nuclei (AGN) versus other spectral classes, for example, HII region-like (HII), transition objects (TRAN), passive (PAS), and retired (RET), in a complete set of galaxies in the local Universe is of primary importance to discriminate the source of ionization in the nuclear region of galaxies (e.g., supermassive black holes vs. young and old stars). Here we aim to provide a spectroscopic characterization of the nuclei of galaxies belonging to the Herschel Reference Survey (HRS), a volume and magnitude limited sample representative of the local Universe, which has become a benchmark for local and high- z studies, for semianalytical models and cosmological simulations. The comparison between the nuclear spectral classification and the one determined on the global galactic scale provides information about how galaxy properties change from the nuclear to the outer regions. Moreover, the extrapolation of the global star formation (SF) properties from the SDSS fiber spectroscopy compared to the one computed by H{alpha} photometry can be useful for testing the method based on aperture correction for determining the global star formation rate for local galaxies. By collecting the existing nuclear spectroscopy available from the literature, complemented with new observations obtained using the Loiano 1.52m telescope, we analyze the 322 nuclear spectra of HRS galaxies; their integrated spectroscopy is available from the literature as well. Using two diagnostic diagrams (the BPT and the WHAN) we provide a nuclear and an integrated spectral classification for the HRS galaxies. The BPT and the WHAN methods for nuclei consistently give a frequency of 53-64% HII, around 21-27% AGNs (including TRAN), and 15-20% of PAS (including RET), whereas for integrated spectra they give 69-84% HII, 4-11% of AGNs and 12-20% PAS. Solely among late-type galaxies (LTGs) do the nuclear percentages become 67-77% HII, 22-27% AGNs (including TRAN), and only 1-7% of PAS. For the integrated spectra these frequencies become: 80-85% HII, 9-11% AGNs and 4-9% PAS. We find that the fraction of HII region-like spectra is strongly anticorrelated with the stellar mass. On the contrary the frequency of AGNs increases significantly with stellar mass, such that at M*>10^10.0^M_{sun}_~66% of the LTGs are AGNs or TRAN. Moreover there is not a significant dependence of the frequency of AGNs as a function of environment: AGNs+TRAN above 10^9.0^M_{sun}_ are consistent with ~30% irrespective of their membership to the Virgo cluster, suggesting that the AGNs population is not sensitive to the environment. Finally, extrapolation of the global SF properties from the nuclear spectroscopy including aperture corrections leads to underestimates with respect to values derived from direct integrated H{alpha} photometry.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A33
- Title:
- HRS sample stellar, dust, gas mass functions
- Short Name:
- J/A+A/617/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the results of the relationships between the K-band and stellar mass, far-infrared luminosities, star formation rate, dust and gas masses of nearby galaxies computing the bivariate K-band Luminosity Function (BLF) and bivariate K-band Mass Function (BMF) of the Herschel Reference Survey (HRS), a volume-limited sample with full wavelength coverage. We derive the BLFs and BMFs from the K-band and stellar mass, far-infrared luminosities, star formation rate, dust and gas masses cumulative distributions using a copula method which is outlined in detail. The use of the bivariate computed taking into account the upper limits allows us to derive on a more solid statistical ground the relationship between the observed physical quantities. The analysis shows that the behaviour of the morphological (optically selected) subsamples is quite different. A statistically meaningful result can be obtained over the whole HRS sample only from the relationship between the K-band and the stellar mass, while for the remaining physical quantities (dust and gas masses, far-IR luminosity and star formation rate), the analysis is distinct for late-type (LT) and early-type galaxies (ETG). However, the number of ETGs is small to perform a robust statistical analysis, and in most of the case results are discussed only for the LTG subsample. The Luminosity and Mass Functions (LFs, MFs) of LTGs are generally dependent on the K-band and the various dependencies are discussed in detail. We are able to derive the corresponding LFs and MFs and compare them with those computed with other samples. Our statistical analysis allows us to characterise the HRS, that, although non homogeneously selected and partially biased towards low IR luminosities, may be considered as representative of the local LT galaxy population.
- ID:
- ivo://CDS.VizieR/J/AJ/159/103
- Title:
- HSC search of SDSS and GAMA dwarf gal. mergers
- Short Name:
- J/AJ/159/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Like massive galaxies, dwarf galaxies are expected to undergo major mergers with other dwarfs. However, the end state of these mergers and the role that merging plays in regulating dwarf star formation are uncertain. Using imaging from the Hyper Suprime-Cam Subaru Strategic Program, we construct a sample of dwarf-dwarf mergers and examine the star formation and host properties of the merging systems. These galaxies are selected via an automated detection algorithm from a sample of 6875 spectroscopically selected isolated dwarf galaxies at z<0.12 and log(M_*_/M_{sun}_)<9.6 from the Galaxy and Mass Assembly and Sloan Digital Sky Survey spectroscopic campaigns. We find a total tidal feature detection fraction of 3.29% (6.1% when considering only galaxies at z<0.05). The tidal feature detection fraction rises strongly as a function of star formation activity; 15%-20% of galaxies with extremely high H{alpha} equivalent width (EW_H{alpha}_>250{AA}) show signs of tidal debris. Galaxies that host tidal debris are also systematically bluer than the average galaxy at fixed stellar mass. These findings extend the observed dwarf-dwarf merger sequence with a significant sample of dwarf galaxies, indicating that star formation triggered in mergers between dwarf galaxies continues after coalescence.
- ID:
- ivo://CDS.VizieR/J/ApJ/780/34
- Title:
- H_160_-selected catalog of galaxies in the HUDF
- Short Name:
- J/ApJ/780/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of an H_160_-selected photometric catalog of galaxies in the Hubble Ultra-Deep Field, using imaging from the WFC3/IR camera on the Hubble Space Telescope in combination with archival ultraviolet, optical, and near-infrared imaging. Using these data, we measure the spectral energy distributions of ~1500 galaxies to a limiting H_160_ magnitude of 27.8, from which we fit photometric redshifts and stellar population estimates for all galaxies with well-determined Spitzer IRAC fluxes, allowing for the determination of the cumulative mass function within the range 1<z<6. By selecting samples of galaxies at a constant cumulative number density, we are able to explore the coevolution of stellar masses and star formation rates (SFRs) for progenitor galaxies and their descendants from z~6. We find a steady increase in the SFRs of galaxies at constant number density from z~6 to z~3, accompanied by gradually declining specific star formation rates (sSFRs) during this same period. The peak epoch of star formation is also found to shift to later times for galaxies with increasing number densities, in agreement with the expectations from cosmic downsizing. The observed SFRs can fully account for the mass growth to z~2 among galaxies with cumulative number densities greater than 10^-3.5^Mpc^-3^. For galaxies with a lower constant number density (higher mean mass), we find the observed stellar masses are ~three times greater than that which may be accounted for by the observed star formation alone at late times, implying that growth from mergers plays an important role at z<2. We additionally observe a decreasing sSFR, equivalent to approximately one order of magnitude, from z~6 to z~2 among galaxies with number densities less than 10^-3.5^Mpc^3^, along with significant evidence that at any redshift the sSFR is higher for galaxies at higher number density. The combination of these findings can qualitatively explain the previous findings of a specific star formation rate plateau at high redshift. Tracing the evolution of the fraction of quiescent galaxies for samples matched in cumulative number density over this redshift range, we find no unambiguous examples of quiescent galaxies at z>4.
- ID:
- ivo://CDS.VizieR/J/ApJS/191/143
- Title:
- HST/ACS Coma cluster survey. II.
- Short Name:
- J/ApJS/191/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Coma cluster, Abell 1656, was the target of an HST-ACS Treasury program designed for deep imaging in the F475W and F814W passbands. Although our survey was interrupted by the ACS instrument failure in early 2007, the partially completed survey still covers ~50% of the core high-density region in Coma. Observations were performed for 25 fields that extend over a wide range of cluster-centric radii (1.75Mpc or 1{deg}) with a total coverage area of 274arcmin^2^. The majority of the fields are located near the core region of Coma (19/25 pointings) with six additional fields in the southwest region of the cluster. In this paper, we present reprocessed images and SEXTRACTOR source catalogs for our survey fields, including a detailed description of the methodology used for object detection and photometry, the subtraction of bright galaxies to measure faint underlying objects, and the use of simulations to assess the photometric accuracy and completeness of our catalogs. We also use simulations to perform aperture corrections for the SEXTRACTOR Kron magnitudes based only on the measured source flux and its half-light radius. We have performed photometry for 73,000 unique objects; approximately one-half of our detections are brighter than the 10{sigma} point-source detection limit at F814W=25.8mag(AB). The slight majority of objects (60%) are unresolved or only marginally resolved by ACS. We estimate that Coma members are 5%-10% of all source detections, which consist of a large population of unresolved compact sources (primarily globular clusters but also ultra-compact dwarf galaxies) and a wide variety of extended galaxies from a cD galaxy to dwarf low surface brightness galaxies. The red sequence of Coma member galaxies has a color-magnitude relation with a constant slope and dispersion over 9mag (-21<M_I_<-13). The initial data release for the HST-ACS Coma Treasury program was made available to the public in 2008 August. The images and catalogs described in this study relate to our second data release.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/3052
- Title:
- HST/ACS Coma Cluster Survey. VI.
- Short Name:
- J/MNRAS/414/3052
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using deep, high-spatial-resolution imaging from the Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) Coma Cluster Treasury Survey, we determine colour profiles of early-type galaxies in the Coma cluster. From 176 galaxies brighter than MF814W(AB)=-15mag that are either spectroscopically confirmed members of Coma or identified by eye as likely members from their low surface brightness, data are provided for 142 early-type galaxies. Typically, colour profiles are linear against log (R), sometimes with a nuclear region of distinct, often bluer colour associated with nuclear clusters. Colour gradients are determined for the regions outside the nuclear components. We find that almost all colour gradients are negative, both for elliptical and for lenticular galaxies. Most likely, earlier studies that report positive colour gradients in dwarf galaxies are affected by the bluer colours of the nuclear clusters, underlining that high-resolution data are essential to disentangle the colour properties of the different morphological components in galaxies. Colour gradients of dwarf galaxies form a continuous sequence with those of elliptical galaxies, becoming shallower towards fainter magnitudes. Interpreting the colours as metallicity tracers, our data suggest that dwarfs as well as giant early-type galaxies in the Coma cluster are less metal rich in their outer parts. We do not find evidence for environmental influence on the gradients, although we note that most of our galaxies are found in the central regions of the cluster. For a subset of galaxies with known morphological types, S0 galaxies have less steep gradients than elliptical galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/445/2385
- Title:
- HST/ACS Coma Cluster Survey. X.
- Short Name:
- J/MNRAS/445/2385
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present scaling relations between structural properties of nuclear star clusters and their host galaxies for a sample of early-type dwarf galaxies observed as part of the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Coma Cluster Survey. We have analysed the light profiles of 200 early-type dwarf galaxies in the magnitude range 16.0<m_F814W_<22.6mag, corresponding to -19.0<M_F814W_<-12.4mag. Nuclear star clusters are detected in 80 percent of the galaxies, thus doubling the sample of HST-observed early-type dwarf galaxies with nuclear star clusters. We confirm that the nuclear star cluster detection fraction decreases strongly towards faint magnitudes. The luminosities of nuclear star clusters do not scale linearly with host galaxy luminosity. A linear fit yields L_nuc_~L_gal_^0.57^+/-0.05. The nuclear star cluster-host galaxy luminosity scaling relation for low-mass early-type dwarf galaxies is consistent with formation by globular cluster (GC) accretion. We find that at similar luminosities, galaxies with higher Sersic indices have slightly more luminous nuclear star clusters. Rounder galaxies have on average more luminous clusters. Some of the nuclear star clusters are resolved, despite the distance of Coma. We argue that the relation between nuclear star cluster mass and size is consistent with both formation by GC accretion and in situ formation. Our data are consistent with GC inspiralling being the dominant mechanism at low masses, although the observed trend with Sersic index suggests that in situ star formation is an important second-order effect.
