- ID:
- ivo://CDS.VizieR/J/ApJ/532/308
- Title:
- Hot Horizontal Branch Stars in the Core of M32
- Short Name:
- J/ApJ/532/308
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1.dat contains the STIS near-UV photometry for the hot stars in the core of M32. The catalog includes 8021 stars, and gives position in the STIS image, magnitude, error, region of the image, RA (J2000), and Dec (J2000). The photometry was performed in six distinct regions of the image because of changes in the point spread function across the image. Note that the relative astrometry is quite accurate (tenths of a 0.025 arcsec STIS pixel), but the absolute astrometry is subject to a 1-2 arcsec uncertainty (associated with the position of the guide stars). Three stars were marked with a footnote in the published catalog, because they are associated with planetary nebulae in our field; they are at the following positions (x,y): (354.949, 821.325), (717.148, 669.210), and (994.924, 355.956).
Number of results to display per page
Search Results
- 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>).
- ID:
- ivo://CDS.VizieR/J/AJ/138/606
- Title:
- Hot subdwarf stars in rejected PG catalog
- Short Name:
- J/AJ/138/606
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The hot subdwarf (sd) stars in the Palomar Green (PG) catalog of ultraviolet excess (UVX) objects play a key role in investigations of the frequency and types of binary companions and the distribution of orbital periods. These are important for establishing whether and by which channels the sd stars arise from interactions in close binary systems. It has been suggested that the list of PG sd stars is biased by the exclusion of many stars in binaries, whose spectra show the CaII K line in absorption. A total of 1125 objects that were photometrically selected as candidates were ultimately rejected from the final PG catalog using this K-line criterion. We study 88 of these "PG-Rejects" (PGRs), to assess whether there are significant numbers of unrecognized sd stars in binaries among the PGR objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/794/75
- Title:
- HST-COS UV spectra observations of AGNs
- Short Name:
- J/ApJ/794/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ionizing fluxes from quasars and other active galactic nuclei (AGNs) are critical for interpreting their emission-line spectra and for photoionizing and heating the intergalactic medium. Using far-ultraviolet (FUV) spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), we directly measure the rest-frame ionizing continua and emission lines for 159 AGNs at redshifts 0.001<z_AGN_<1.476 and construct a composite spectrum from 475 to 1875 {AA}. We identify the underlying AGN continuum and strong extreme ultraviolet (EUV) emission lines from ions of oxygen, neon, and nitrogen after masking out absorption lines from the H I Ly{alpha} forest, 7 Lyman-limit systems (N_HI_>=10^17.2^/cm2) and 214 partial Lyman-limit systems (14.5<logN_HI_<17.2). The 159 AGNs exhibit a wide range of FUV/EUV spectral shapes, F_v_{propto}{nu}^{alpha}_{nu}_^, typically with -2<={alpha}_{nu}_<=0 and no discernible continuum edges at 912 {AA} (H I) or 504 {AA} (He I). The composite rest-frame continuum shows a gradual break at {lambda}_br_{approx} 1000 {AA}, with mean spectral index {alpha}_{nu}_=-0.83+/-0.09 in the FUV (1200-2000 {AA}) steepening to {alpha}_{nu}_=-1.41+/-0.15 in the EUV (500-1000 {AA}). We discuss the implications of the UV flux turnovers and lack of continuum edges for the structure of accretion disks, AGN mass inflow rates, and luminosities relative to Eddington values.
- ID:
- ivo://CDS.VizieR/J/ApJS/128/99
- Title:
- HST photometry of 4 Virgo LSB galaxies
- Short Name:
- J/ApJS/128/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Utilizing the F814W and F300W filters, Hubble Space Telescope Wide Field Planetary Camera-2 (WFPC2) images were taken of four low surface brightness galaxies in the direction of the Virgo Cluster - V7L3, V2L8, V1L4, and Malin 1. The high resolution of the WFPC2 combined with the extremely diffuse nature of the four galaxies makes them essentially transparent, allowing for the serendipitous discovery of 139 background galaxies visible through both the disks and nuclei of the foreground galaxies. Surface photometry was done on the newly discovered galaxies through the F814W (I-band) filter. The detected galaxies have both r1/4 and exponential-type profiles with radii (to the {mu}_F814W_=25.0mag/arcsec^2^ limit) less than 5.0". Their total magnitudes range from 18.9 through the survey cutoff at 25.0 in the F814W filter.
- ID:
- ivo://CDS.VizieR/J/A+A/391/857
- Title:
- HST UV,V,I photometry of NGC7673 star clusters
- Short Name:
- J/A+A/391/857
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the star cluster system in the starburst galaxy NGC 7673 using archival Hubble Space Telescope WFPC2 broad-band images. For the first time we are able to examine the internal structures of the prominent optical clumps in this galaxy. The clumps are composed of young stars, 16-33% of which are in bright star clusters. We identify 268 star cluster candidates in both the F555W and F814W images, and 50 clusters with the F255W filter. These data allow us to estimate ages and masses using color-magnitude and two-color diagrams for our sample. We find a population of young, <6Myr clusters located throughout the galaxy with concentrations in the clumps. Star cluster mass estimates are 5-50x10^4^M_{sun}_ for the brightest objects. The starburst remains active in physically well-separated regions, indicating a widespread starburst trigger. We discuss clump lifetimes, their implications for the future evolution of NGC 7673, and possible relationships to high redshift starbursts.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A7
- Title:
- Hyades single stars fiducial photometry
- Short Name:
- J/A+A/585/A7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Age and mass determinations for isolated stellar objects remain model-dependent. While stellar interior and atmospheric theoretical models are rapidly evolving, we need a powerful tool to test them. Open clusters are good candidates for this role. We aim to create a fiducial sequence of stellar objects for testing stellar and atmospheric models. We complement previous studies on the Hyades multiplicity by Lucky Imaging observations with the AstraLux Norte camera. This allows us to exclude possible binary and multiple systems with companions outside 2-7AU separation and to create a "single-star sequence" for the Hyades. The sequence encompasses 250 main-sequence stars ranging from A5V to M6V. Using the "Tool for Astrophysical Data Analysis" (TA-DA), we create various theoretical isochrones applying different combinations of interior and atmospheric models. We compare the isochrones with the observed Hyades single-star sequence on J vs. J-Ks, J vs. J-H and Ks vs. H-Ks color-magnitude diagrams. As a reference we also compute absolute fluxes and magnitudes for all stars from X-ray to mid-infrared based on photometric measurements available in the literature (ROSAT X-ray, GALEX UV, APASS gri, 2MASS JHKs, and WISE W1 to W4). We find that combinations of both PISA and DARTMOUTH stellar interior models with BT-Settl 2010 atmospheric models describe the observed sequence well. We use PISA in combination with BT-Settl 2010 models to derive theoretical predictions for physical parameters (Teff, mass, logg) of 250 single stars in the Hyades. The full sequence covers the mass range 0.13 to 2.3M_{sun}_, and effective temperatures between 3060K and 8200K. Conclusions. Within the measurement uncertainties, the current generation of models agree well with the single-star sequence. The primary limitations are the uncertainties in the measurement of the distance to individual Hyades members, and uncertainties in the photometry. Gaia parallaxes, photometry and spectroscopy will greatly reduce the uncertainties in particular at the lowest mass range, and will enable us to test model predictions with greater confidence. Additionally, a small (~0.05mag) systematic offset can be noted on J vs. J-K and K vs. H-K diagrams - the observed sequence is shifted to redder colors from the theoretical predictions.
- ID:
- ivo://CDS.VizieR/V/165
- Title:
- IGAPS. merged IPHAS and UVEX of northern Galactic plane
- Short Name:
- V/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The INT Galactic Plane Survey (IGAPS) is the merger of the optical photometric surveys, IPHAS and UVEX, based on data from the Isaac Newton Telescope (INT) obtained between 2003 and 2018. Here, we present the IGAPS point source catalogue. It contains 295.4 million rows providing photometry in the filters, i, r, narrow-band H{alpha}, g, and URGO. The IGAPS footprint fills the Galactic coordinate range, |b|<5{deg} and 30{deg}<l<215{deg}. A uniform calibration, referred to as the Pan-STARRS system, is applied to g, r, and i, while the H{alpha} calibration is linked to r and then is reconciled via field overlaps. The astrometry in all five bands has been recalculated in the reference frame of Gaia Data Release 2. Down to i~20mag (Vega system), most stars are also detected in g, r, and H{alpha}. As exposures in the r band were obtained in both the IPHAS and UVEX surveys, typically a few years apart, the catalogue includes two distinct r measures, r_I_ and r_U_. The r 10{sigma} limiting magnitude is approximately 21, with median seeing of 1.1arcsec. Between approximately 13^th^ and 19^th^ mag in all bands, the photometry is internally reproducible to within 0.02 magnitudes. Stars brighter than r=19.5mag are tested for narrow-band H{alpha} excess signalling line emission, and for variation exceeding |r_I_-r_U_|=0.2mag. We find and flag 8292 candidate emission line stars and over 53000 variables (both at >5{sigma} confidence).
- ID:
- ivo://CDS.VizieR/J/BaltA/11/1
- Title:
- Interstellar extinction curves of OB stars
- Short Name:
- J/BaltA/11/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper presents a collection of 436 extinction curves covering the whole available range of wavelengths from satellite UV to near-IR. The data were taken from the ANS photometric catalogue (Cat. <II/97>) and from the compilations of IR photometric measurements. The data curves have been obtained with the aid of "artificial standards" Papaj et al. (1993A&A...273..575P) and Wegner (1994MNRAS.270..229W, 1995, Interstellar Absorption Structures in the Direction of Nearby OB stars, Wyd. Uczelniane WSP, Bydgoszcz, p. 1-383). The visual magnitudes and spectral classifications of O and B type stars with E_B-V_>=0.05 were taken from the SIMBAD database. The curves are given in the form of plots and tables E_{lambda}-V_/E_B-V_ versus 1/{lambda}. The observed variety of extinction laws among slightly reddened stars is apparently due to the various physical parameters of interstellar clouds.
- ID:
- ivo://CDS.VizieR/J/ApJS/199/23
- Title:
- IR and UV star formation in ACCEPT BCGs
- Short Name:
- J/ApJS/199/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present infrared (IR) and ultraviolet (UV) photometry for a sample of brightest cluster galaxies (BCGs). The BCGs are from a heterogeneous but uniformly characterized sample, the Archive of Chandra Cluster Entropy Profile Tables (ACCEPT), of X-ray galaxy clusters from the Chandra X-ray telescope archive with published gas temperature, density, and entropy profiles. We use archival Galaxy Evolution Explorer (GALEX), Spitzer Space Telescope, and Two Micron All Sky Survey (2MASS) observations to assemble spectral energy distributions (SEDs) and colors for BCGs. We establish a mean near-UV (NUV) to 2MASS K color of 6.59+/-0.34 for quiescent BCGs. We use this mean color to quantify the UV excess associated with star formation in the active BCGs. We use both fits to a template of an evolved stellar population and library of starburst models and mid-IR star formation relations to estimate the obscured star formation rates (SFRs). We present IR and UV photometry and estimated equivalent continuous SFRs for a sample of BCGs.
