- ID:
- ivo://CDS.VizieR/J/PASP/120/1128
- Title:
- Calibrated griz magnitudes of Tycho stars
- Short Name:
- J/PASP/120/1128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric calibration at an accuracy of ~5% in an arbitrary celestial location is frequently needed. However, existing all-sky astronomical catalogue do not reach this accuracy, and time consuming photometric calibration procedures are required. I fitted the Hipparcos B_T_, and V_T_ magnitudes, along with the 2MASS J, H, and K magnitudes of Tycho-2 catalog-stars with stellar spectral templates. From the best fit spectral template derived for each star, I calculated its synthetic SDSS griz magnitudes, and constructed an all-sky catalog of griz magnitudes of bright stars (V<12). Testing this method on SDSS photometric telescope observations, I find that the photometric accuracy, for a single star, is usually about 0.12, 0.12, 0.10 and 0.08 mag (1sigma), for the g, r, i, and z-bands, respectively. However, by using ~10 such stars, the typical errors per calibrated field (systematic + statistical) can be reduced to about 0.04, 0.03, 0.02, and 0.02 mag, in the g, r, i, and z-bands, respectively. Therefore, in cases for which several calibration stars can be observed in the field of view of an instrument, it is possible to photometrically calibrate the image.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/585/A47
- Title:
- CALIFA color/metallicity gradients connections
- Short Name:
- J/A+A/585/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study, for the first time in a statistically significant and well-defined sample, the relation between the outer-disk ionized-gas metallicity gradients and the presence of breaks in the surface brightness profiles of disk galaxies. Sloan Digital Sky Survey (SDSS) g'- and r'-band surface brightness, (g'-r') color, and ionized-gas oxygen abundance profiles for 324 galaxies within the Calar Alto Legacy Integral Field Area (CALIFA) survey are used for this purpose. We perform a detailed light-profile classification, finding that 84% of our disks show down- or up-bending profiles (Type II and Type III, respectively), while the remaining 16% are well fitted by one single exponential (Type I). The analysis of the color gradients at both sides of this break shows a U-shaped profile for most Type II galaxies with an average minimum (g'-r') color of ~0.5mag and an ionized-gas metallicity flattening associated with it only in the case of low-mass galaxies. Comparatively, more massive systems show a rather uniform negative metallicity gradient. The correlation between metallicity flattening and stellar mass for these systems results in p-values as low as 0.01. Independent of the mechanism having shaped the outer light profiles of these galaxies, stellar migration or a previous episode of star formation in a shrinking star-forming disk, it is clear that the imprint in their ionized-gas metallicity was different for low- and high-mass Type II galaxies. In the case of Type III disks, a positive correlation between the change in color and abundance gradient is found (the null hypothesis is ruled out with a p-value of 0.02), with the outer disks of Type III galaxies with masses <=10^10^M_{sun}_ showing a weak color reddening or even a bluing. This is interpreted as primarily due to a mass downsizing effect on the population of Type III galaxies that recently experienced an enhanced inside-out growth.
53. CALIFA DR2
- ID:
- ivo://CDS.VizieR/J/A+A/576/A135
- Title:
- CALIFA DR2
- Short Name:
- J/A+A/576/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper describes the Second Public Data Release (DR2) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. The data for 200 objects are made public, including the 100 galaxies of the First Public Data Release (DR1). Data were obtained with the integral-field spectrograph PMAS/PPak mounted on the 3.5m telescope at the Calar Alto observatory. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the wavelength range 3745-7500{AA} with a spectral resolution of 6.0{AA} (FWHM); and (ii) a medium-resolution V1200 setup covering the wavelength range 3650-4840{AA} with a spectral resolution of 2.3{AA} (FWHM). The sample covers a redshift range between 0.005 and 0.03, with a wide range of properties in the color-magnitude diagram, stellar mass, ionization conditions, and morphological types. All the cubes in the data release were reduced with the latest pipeline, which includes improved spectrophotometric calibration, spatial registration, and spatial resolution. The spectrophotometric calibration is better than 6% and the median spatial resolution is 2.4". In total, the second data release contains over 1.5 million spectra.
- ID:
- ivo://CDS.VizieR/J/MNRAS/492/3073
- Title:
- CALIFA galaxies hosting an AGN
- Short Name:
- J/MNRAS/492/3073
- Date:
- 02 Feb 2022 07:33:25
- Publisher:
- CDS
- Description:
- We study the presence of optically-selected Active Galactic Nuclei (AGNs) within a sample of 867 galaxies extracted from the extended Calar-Alto Legacy Integral Field spectroscopy Area (eCALIFA) spanning all morphological classes. We identify 10 Type-I and 24 Type-II AGNs, amounting to ~4 per cent of our sample, similar to the fraction reported by previous explorations in the same redshift range. We compare the integrated properties of the ionized and molecular gas, and stellar population of AGN hosts and their non-active counterparts, combining them with morphological information. The AGN hosts are found in transitory parts (i.e. green-valley) in almost all analysed properties which present bimodal distributions (i.e. a region where reside star-forming galaxies and another with quiescent/retired ones). Regarding morphology, we find AGN hosts among the most massive galaxies, with enhanced central stellar-mass surface density in comparison to the average population at each morphological type. Moreover, their distribution peaks at the Sab-Sb classes and none are found among very late-type galaxies (>Scd). Finally, we inspect how the AGN could act in heir hosts regarding the quenching of star-formation. The main role of the AGN in the quenching process appears to be the removal (or heating) of molecular gas, rather than an additional suppression of the already observed decrease of the star-formation efficiency from late-to-early type galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/466/163
- Title:
- Candidate Halpha sources in GBS
- Short Name:
- J/MNRAS/466/163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of candidate Halpha emission and absorption line sources and blue objects in the Galactic Bulge Survey (GBS) region. We use a point source catalogue of the GBS fields (two strips of (lxb)=(6{deg}x1{deg}) centred at b=1.5{deg} above and below the Galactic centre), covering the magnitude range 16>=r'>=22.5. We utilize (r'-i', r'-Halpha) colour-colour diagrams to select Halpha emission and absorption line candidates, and also identify blue objects (compared to field stars) using the r'-i' colour index. We identify 1337 Halpha emission line candidates and 336 Halpha absorption line candidates. These catalogues likely contain a plethora of sources, ranging from active (binary) stars, early-type emission line objects, cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs) to background active galactic nuclei (AGN). The 389 blue objects we identify are likely systems containing a compact object, such as CVs, planetary nebulae and LMXBs. Hot subluminous dwarfs (sdO/B stars) are also expected to be found as blue outliers. Crossmatching our outliers with the GBS X-ray catalogue yields sixteen sources, including seven (magnetic) CVs and one qLMXB candidate among the emission line candidates, and one background AGN for the absorption line candidates. One of the blue outliers is a high state AM CVn system. Spectroscopic observations combined with the multi-wavelength coverage of this area, including X-ray, ultraviolet and (time-resolved) optical and infrared observations, can be used to further constrain the nature of individual sources.
- ID:
- ivo://CDS.VizieR/J/AJ/131/2959
- Title:
- Candidate low-mass PMS in 25 Orionis group
- Short Name:
- J/AJ/131/2959
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The stellar group surrounding the Be (B1Vpe) star 25 Ori was discovered to be a pre-main-sequence (PMS) population by the CIDA Variability Survey of Orion (Cat. J/AJ/129/907) and subsequent spectroscopy. We analyze Sloan Digital Sky Survey multiepoch photometry to map the southern extent of the 25 Ori group and characterize its PMS population. We compare this group to the neighboring Orion OB1a and OB1b subassociations and to active star formation sites (NGC 2068/NGC 2071) within the LDN 1630 dark cloud. We find that the 25 Ori group has a radius of 1.4{deg}, corresponding to 8-11pc at the distances of Orion OB1a and OB1b.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/281
- Title:
- Candidate rotating M dwarfs from PS1-MDS
- Short Name:
- J/ApJ/833/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on an ongoing project to investigate activity in the M dwarf stellar population observed by the Pan-STARRS1 Medium-Deep Survey (PS1-MDS). Using a custom-built pipeline, we refine an initial sample of ~4 million sources in PS1-MDS to a sample of 184148 candidate cool stars using color cuts. Motivated by the well-known relationship between rotation and stellar activity, we use a multiband periodogram analysis and visual vetting to identify 270 sources that are likely rotating M dwarfs. We derive a new set of polynomials relating M dwarf PS1 colors to fundamental stellar parameters and use them to estimate the masses, distances, effective temperatures, and bolometric luminosities of our sample. We present a catalog containing these values, our measured rotation periods, and cross-matches to other surveys. Our final sample spans periods of <~1-130 days in stars with estimated effective temperatures of ~2700-4000K. Twenty-two of our sources have X-ray cross-matches, and they are found to be relatively X-ray bright as would be expected from selection effects. Our data set provides evidence that Kepler-based searches have not been sensitive to very slowly rotating stars (P_rot_>~70 day), implying that the observed emergence of very slow rotators in studies of low-mass stars may be a systematic effect. We also see a lack of low-amplitude (<2%) variability in objects with intermediate (10-40 day) rotation periods, which, considered in conjunction with other observational results, may be a signpost of a loss of magnetic complexity associated with a phase of rapid spin-down in intermediate-age M dwarfs. This work represents just a first step in exploring stellar variability in data from the PS1-MDS and, in the farther future, Large Synoptic Survey Telescope.
- ID:
- ivo://CDS.VizieR/J/A+A/444/643
- Title:
- Candidate spectroscopic binaries in SDSS
- Short Name:
- J/A+A/444/643
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have examined the radial velocity data for stars spectroscopically observed by the Sloan Digital Sky Survey (SDSS) more than once to investigate the incidence of spectroscopic binaries, and to evaluate the accuracy of the SDSS stellar radial velocities.
- ID:
- ivo://CDS.VizieR/J/ApJ/765/12
- Title:
- Carbon stars and DQ white dwarfs from SDSS-DR7+DR8
- Short Name:
- J/ApJ/765/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Among stars showing carbon molecular bands (C stars), the main-sequence dwarfs, likely in post-mass transfer binaries, are numerically dominant in the Galaxy. Via spectroscopic selection from the Sloan Digital Sky Survey, we retrieve 1220 high galactic latitude C stars, ~5 times more than previously known, including a wider variety than past techniques such as color or grism selection have netted, and additionally yielding 167 DQ white dwarfs. Of the C stars with proper motion measurements, we identify 69% clearly as dwarfs (dCs), while ~7% are giants. The dCs likely span absolute magnitudes M_i_ from ~6.5 to 10.5. "G-type" dC stars with weak CN and relatively blue colors are probably the most massive dCs still cool enough to show C_2_bands. We report Balmer emission in 22 dCs, none of which are G-types. We find 8 new DA/dC stars in composite spectrum binaries, quadrupling the total sample of these "smoking guns" for AGB binary mass transfer. Eleven very red C stars with strong red CN bands appear to be "N"-type AGB stars at large Galactocentric distances, one likely a new discovery in the dIrr galaxy Leo A. Two such stars within 30' of each other may trace a previously unidentified dwarf galaxy or tidal stream at ~40 kpc. We explore the multiwavelength properties of the sample and report the first X-ray detection of a dC star, which shows strong Balmer emission. Our own spectroscopic survey additionally provides the dC surface density from a complete sample of dwarfs limited by magnitude, color, and proper motion.
- ID:
- ivo://CDS.VizieR/J/AJ/139/519
- Title:
- Carnegie supernova project. SNe Ia
- Short Name:
- J/AJ/139/519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Carnegie Supernova Project (CSP) is a five-year survey being carried out at the Las Campanas Observatory to obtain high-quality light curves of ~100 low-redshift Type Ia supernovae (SNe Ia) in a well-defined photometric system. Here we present the first release of photometric data that contains the optical light curves of 35 SNe Ia, and near-infrared light curves for a subset of 25 events. The data comprise 5559 optical (ugriBV) and 1043 near-infrared (Y JHKs) data points in the natural system of the Swope telescope. Twenty-eight SNe have pre-maximum data, and for 15 of these, the observations begin at least 5 days before B maximum. This is one of the most accurate data sets of low-redshift SNe Ia published to date. When completed, the CSP data set will constitute a fundamental reference for precise determinations of cosmological parameters, and serve as a rich resource for comparison with models of SNe Ia.
