- ID:
- ivo://CDS.VizieR/J/AJ/157/35
- Title:
- The population of pulsating variable stars in Sextans
- Short Name:
- J/AJ/157/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large extension of the Sextans dwarf spheroidal galaxy, 7 deg^2^, has been surveyed for variable stars using the Dark Energy Camera at the Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile. We report seven anomalous Cepheids, 199 RR Lyrae stars, and 16 dwarf Cepheids in the field. This is only the fifth extragalactic system in which dwarf Cepheids have been systematically searched. Henceforth, the new stars increase the census of stars coming from different environments that can be used to asses the advantages and limitations of using dwarf Cepheids as standard candles in populations for which the metallicity is not necessarily known. The dwarf Cepheids found in Sextans have a mean period of 0.066 day and a mean g amplitude of 0.87 mag. They are located below the horizontal branch, spanning a range of 0.8 mag: 21.9<g<22.7. The number of dwarf Cepheids in Sextans is low compared with other galaxies such as Carina, which has a strong intermediate-age population. On the other hand, the number and ratio of RR Lyrae stars to dwarf Cepheids are quite similar to those of Sculptor, a galaxy which, as Sextans, is dominated by an old stellar population. The dwarf Cepheid stars found in Sextans follow a well-constrained period-luminosity relationship with an rms=0.05 mag in the g band, which was set up by anchoring to the distance modulus given by the RR Lyrae stars. Although the majority of the variable stars in Sextans are located toward the center of the galaxy, we have found two RR Lyrae stars and one anomalous Cepheid in the outskirts of the galaxy that may be extratidal stars and suggest that this galaxy may be undergoing tidal destruction. These possible extratidal variable stars share the same proper motions as Sextans, as seen by recent Gaia measurements. Two additional stars that we initially classified as foreground RR Lyrae stars may actually be other examples of Sextans extratidal anomalous Cepheids, although radial velocities are needed to prove that scenario.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/245/6
- Title:
- The 2RMS catalog in the Zone of Avoidance
- Short Name:
- J/ApJS/245/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Two Micron All-Sky Survey (2MASS) Redshift Survey was started two decades ago with the goal of mapping the three-dimensional distribution of an all-sky flux-limited (Ks<11.75mag) sample of ~45000 galaxies. Our first data release presented an unprecedented uniform coverage for most of the celestial sphere, with redshifts for ~98% of our sample. However, we were missing redshifts for ~18% of the catalog entries that were located within the "Zone of Avoidance" (|b|<10{deg})-an important region of the sky for studies of the large-scale structure and cosmic flows. In this second and final data release, we present redshifts for all 1041 2MRS galaxies that previously lacked this information, as well as updated measurements for 27 others.
- ID:
- ivo://CDS.VizieR/VII/274
- Title:
- The Roma BZCAT - 5th edition
- Short Name:
- VII/274
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Roma-BZCAT is now at the 5th Edition which contains coordinates and multi-frequency data of 3561 sources, about 30% more than in the 1st edition, either confirmed blazars or exhibiting characteristics close to this type of sources. With respect to the previous editions, this new edition has relevant changes in the sources' classification and has a new format for the notes in the tables. We emphasize that all the sources in the Roma-BZCAT have a detection in the radio band. Moreover, a complete spectroscopic information is published and could be accessed by us for all of them, with the exception of BL Lac candidates. Consequently, peculiar sources as the so called "radio quiet BL Lacs", which are reported in some other catalogues, are not included here because of possible contamination with hot stars and other extragalactic objects.
3824. The SDSS extended PSFs
- ID:
- ivo://CDS.VizieR/J/MNRAS/491/5317
- Title:
- The SDSS extended PSFs
- Short Name:
- J/MNRAS/491/5317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A robust and extended characterization of the Point Spread Function (PSF) is crucial to extract the photometric information produced by deep imaging surveys. Here we present the extended PSFs of the Sloan Digital Sky Survey (SDSS), one of the most productive astronomical surveys of all time. By stacking ~1000 images of individual stars with different brightness, we obtain the bidimensional SDSS PSFs extending over 8 arcmin in radius for all the SDSS filters (u, g, r, i, z). This new characterization of the SDSS PSFs is near a factor of 10 larger in extension than previous PSFs characterizations of the same survey. We found asymmetries in the shape of the PSFs caused by the drift scanning observing mode. The flux of the PSFs is larger along the drift scanning direction. Following a reproducible science philosophy, we make all the PSF models and the used tools publicly available. Finally, we illustrate with an example how the PSF models can be used to remove the scattered light field produced by the brightest stars in the Coma Cluster central region. This particular example shows the huge importance of PSFs in the study of the low surface brightness Universe, especially with the upcoming of ultra-deep surveys such as the Large Synoptic Survey Telescope (LSST).
3825. The shape of galaxies
- ID:
- ivo://edu.gavo.org/eurovo/aida_galaxies
- Title:
- The shape of galaxies
- Date:
- 27 Dec 2024 08:31:06
- Publisher:
- The GAVO DC team
- Description:
- Within this use case you discover the shapes of galaxies and their classification according to the Hubble diagram. You are offered sequences of galaxies with different morphologies and are asked to order them. The morphological classification of galaxies is still in use even if we have discovered that the Hubble diagram "per se" has no direct physical or evolutionary meaning. Besides introducing the main shapes of galaxies, the use case offer a demonstration of the classification process, a fundamental tool of astronomers.
- ID:
- ivo://CDS.VizieR/J/ApJ/705/1099
- Title:
- The Sloan Lens ACS (SLACS) Survey. IX.
- Short Name:
- J/ApJ/705/1099
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the current photometric data set for the Sloan Lens ACS (SLACS) Survey, including Hubble Space Telescope (HST) photometry from Advanced Camera for Surveys, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade "A" (certain) lens systems, bringing the number of SLACS grade "A" lenses to 85; including 13 grade "B" (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade "A" systems have elliptical morphologies while ~10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for every system, making SLACS the largest homogeneous data set of galaxy-scale lenses to date. The ensemble properties of the SLACS lens galaxies, e.g., stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M_*_>~10^11^M_{sun}_, and are therefore an ideal data set to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z~0.5.
- ID:
- ivo://CDS.VizieR/J/ApJ/690/670
- Title:
- The Sloan lens ACS Survey. VIII.
- Short Name:
- J/ApJ/690/670
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens - the projected number density of galaxies inside the tenth nearest neighbor ({Sigma}_10_) and within a cone of radius 1h^-1^Mpc (D1).
- ID:
- ivo://CDS.VizieR/J/A+A/401/873
- Title:
- The SMC in the Far Infrared
- Short Name:
- J/A+A/401/873
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ISOPHOT experiment onboard the ISO satellite generated a complete view of the Small Magellanic Cloud (SMC) at 170{mu}m with 1.5arcmin resolution. The map is analysed using an automated photometry program enabling accurate photometric characterization of the far infrared (FIR) emitting regions. In this paper, the sources detected at 170{mu}m are compared with those obtainable from the IRAS satellite data. For this purpose, the 12{mu}m, 25{mu}m, 60{mu}m, and 100{mu}m IRAS high resolution (HiRes) maps of the SMC are re-examined using the same method. In contrast to former studies, this provides an all-band ISO/IRAS source catalog which is no longer based on eyeball classification, but relies on an algorithm which is capable of automated, repeatable photometry, even for irregular sources. In the mid infrared IRAS bands numerous bright FIR emitting regions in the SMC are detected and classified: 73 sources are found at 12{mu}m, 135 at 25{mu}m (most of them with F{nu}<1.0Jy). All three FIR bands at 170{mu}m, 100{mu}m, and 60{mu}m reproduce the overall morphological structure of the SMC similarly well, in contrast to the 12{mu}m and 25{mu}m maps which only contain a limited number of extended sources and do not trace the main body of the SMC. 243 sources are detected in the ISO 170{mu}m map, 155 of them with F{nu}>=2.0Jy. Comparable numbers are found for the two FIR IRAS maps at 60{mu}m (384) and 100{mu}m (338) with fluxes up to 450Jy. 70 of the 243 170{mu}m sources are assigned a general SED type (cold , warm , i.e., <30K, >30K) for the first time. A comparison with earlier IRAS results suggests that many source flux densities in those studies have been under- or overestimated because of non-standardized fitting methods. Many sources with flux densities up to 40Jy listed in former catalogs cannot be identified in our data.
- ID:
- ivo://CDS.VizieR/J/ApJ/693/1821
- Title:
- The Spitzer infrared nearby galaxies survey
- Short Name:
- J/ApJ/693/1821
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution mid-infrared spectra are presented for 155 nuclear and extranuclear regions from the Spitzer Infrared Nearby Galaxies Survey (SINGS). The fluxes for nine atomic forbidden and three molecular hydrogen mid-infrared emission lines are also provided, along with upper limits in key lines for infrared-faint targets. The SINGS sample shows a wide range in the ratio of [SIII]18.71um/[SIII]33.48um, but the average ratio of the ensemble indicates a typical interstellar electron density of 300-400cm^-3^ on ~23x15" scales and 500-600cm^-3^ using ~11x9" apertures, independent of whether the region probed is a star-forming nuclear, a star-forming extranuclear, or an active galactic nuclei (AGN) environment.
- ID:
- ivo://CDS.VizieR/J/ApJS/218/6
- Title:
- The Spitzer Interacting Galaxies Survey (SIGS)
- Short Name:
- J/ApJS/218/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer Interacting Galaxies Survey is a sample of 103 nearby galaxies in 48 systems, selected using association likelihoods and therefore free from disturbed morphology biases. All galaxies have been observed with Infrared Array Camera and MIPS 24{mu}m bands from the Spitzer Space Telescope. This catalog presents the global flux densities and colors of all systems and correlations between the interacting systems and their specific star formation rate (sSFR). This sample contains a wide variety of galaxy interactions with systems ranging in mass, mass ratios, and gas-content as well as interaction strength. This study seeks to identify the process of triggering star formation in galaxy interactions, therefore, we focus on the non-active galactic nucleus spiral galaxies only. From this subset of 70 spiral galaxies we have determined that this sample has enhanced sSFR compared to a sample of non-interacting field galaxies. Through optical data we have classified each system by "interaction strength"; the strongly interacting (Stage 4) galaxies have higher sSFR values than the weakly (Stage 2) and moderately (Stage 3) interacting systems. However, the Stage 2 and 3 systems have statistically identical sSFR properties, despite the lack of optical interaction signatures exhibited by the Stage 2 galaxies. We suggest that the similarity of sSFR in these stages could be a consequence of some of these Stage 2 systems actually being post-perigalactic and having had sufficient time for their tidal features to fade to undetectable levels. This interpretation is consistent with the correlation of sSFR with separation, which we have determined to have little variation up to 100kpc.
