- ID:
- ivo://CDS.VizieR/J/AJ/149/117
- Title:
- LMC infrared survey. I. Photometry of Cepheids
- Short Name:
- J/AJ/149/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observational details and first results of a near-infrared (JHK_s_) synoptic survey of the central region of the Large Magellanic Cloud (LMC) using the CPAPIR camera at the CTIO 1.5m telescope. We covered 18 square degrees to a depth of K_s_~16.5mag and obtained an average of 16 epochs in each band at any given location. Our catalog contains more than 3.5x10^6^ sources, including 1417 Cepheid variables previously studied at optical wavelengths by the OGLE survey. Our sample of fundamental-mode pulsators represents a nine-fold increase in the number of these variables with time-resolved, multi-band near-infrared photometry. We combine our large Cepheid sample and a recent precise determination of the distance to the LMC to derive a robust absolute calibration of the near-infrared Leavitt Law for fundamental-mode and first-overtone Cepheids with 10x better constraints on the slopes relative to previous work. We also obtain calibrations for the tip of the red giant branch and the red clump based on our ensemble photometry which are in good agreement with previous determinations.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/153/154
- Title:
- LMC NIR survey. IV. Type II Cepheid variables
- Short Name:
- J/AJ/153/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present time-series observations of Population II Cepheids in the Large Magellanic Cloud at near-infrared (JHK_s_) wavelengths. Our sample consists of 81 variables with accurate periods and optical (VI) magnitudes from the OGLE survey, covering various subtypes of pulsators (BL Herculis, W Virginis, and RV Tauri). We generate light-curve templates using high-quality I-band data in the LMC from OGLE and K_s_-band data in the Galactic bulge from VISTA Variables in Via Lactea survey (2010NewA...15..433M) and use them to obtain robust mean magnitudes. We derive period-luminosity (P-L) relations in the near-infrared and Period-Wesenheit (P-W) relations by combining optical and near-infrared data. Our P-L and P-W relations are consistent with published work when excluding long-period RV Tauris. We find that Pop II Cepheids and RR Lyraes follow the same P-L relations in the LMC. Therefore, we use trigonometric parallax from the Gaia DR1 (Cat. I/337) for VY Pyx and the Hubble Space Telescope parallaxes for k Pav and 5 RR Lyrae variables to obtain an absolute calibration of the Galactic K_s_-band P-L relation, resulting in a distance modulus to the LMC of {mu}_LMC_=18.54+/-0.08 mag. We update the mean magnitudes of Pop II Cepheids in Galactic globular clusters using our light-curve templates and obtain distance estimates to those systems, anchored to a precise late-type eclipsing binary distance to the LMC. We find that the distances to these globular clusters based on Pop II Cepheids are consistent (within 2{sigma}) with estimates based on the M_V_-[Fe/H] relation for horizontal branch stars.
- ID:
- ivo://CDS.VizieR/J/AJ/151/88
- Title:
- LMC NIR Synoptic Survey. II. Wesenheit relations
- Short Name:
- J/AJ/151/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new near-infrared (NIR) Cepheid period-Wesenheit (P-W) relations in the LMC using time-series observations from the Large Magellanic Cloud NIR Synoptic Survey. We also derive optical+NIR P-W relations using V and I magnitudes from the Optical Gravitational Lensing Experiment. We employ our new JHK_s_ data to determine an independent distance to the LMC of {mu}_LMC_=18.47+/-0.07 (statistical) mag, using an absolute calibration of the Galactic relations based on several distance determination methods and accounting for the intrinsic scatter of each technique. We also derive new NIR period-luminosity and Wesenheit relations for Cepheids in M31 using observations from the Panchromatic Hubble Andromeda Treasury survey. We use the absolute calibrations of the Galactic and LMC W_J,H_ relations to determine the distance modulus of M31, {mu}_M31_=24.46+/-0.20 mag. We apply a simultaneous fit to Cepheids in several Local Group galaxies covering a range of metallicities (7.7<12+log[O/H]<8.6 dex) to determine a global slope of -3.244+/-0.016 mag/dex for the W_J,H_ relation and obtain robust distance estimates. Our distances are in good agreement with recent TRGB based distance estimates and we do not find any evidence for a metallicity dependence in the NIR P-W relations.
- ID:
- ivo://CDS.VizieR/J/AJ/154/149
- Title:
- LMC NIR synoptic survey. V. NIR photometry of Miras
- Short Name:
- J/AJ/154/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the near-infrared properties of 690 Mira candidates in the central region of the Large Magellanic Cloud, based on time-series observations at JHK_s_. We use densely sampled I-band observations from the OGLE project to generate template light curves in the near-infrared and derive robust mean magnitudes at those wavelengths. We obtain near-infrared Period-Luminosity relations for oxygen-rich Miras with a scatter as low as 0.12 mag at K_s_. We study the Period-Luminosity-Color relations and the color excesses of carbon-rich Miras, which show evidence for a substantially different reddening law.
- ID:
- ivo://CDS.VizieR/J/AcA/63/159
- Title:
- LMC OGLE-III Shallow Survey variable stars
- Short Name:
- J/AcA/63/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe variable stars found in the data collected during the OGLE-III Shallow Survey covering the I-band magnitude range from 9.7mag to 14.5mag. The main result is the extension of period-luminosity relations for Cepheids up to 134 days. We also detected 82 binary systems and 110 long-period variables not present in the main OGLE catalogs. Additionally 558 objects were selected as candidates for miscellaneous variables.
- ID:
- ivo://CDS.VizieR/J/AcA/62/247
- Title:
- LMC photometric maps from OGLE-III shallow survey
- Short Name:
- J/AcA/62/247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric maps based on data from the shallow survey in the Large Magellanic Cloud performed as the supplementary project during the third phase of the Optical Gravitational Lensing Experiment (OGLE) . They cover about 40 square degrees in the LMC and contain mean calibrated VI photometry and astrometry of about 1.7million stars. The magnitudes of the objects range from 9.1 to 18.5.
- ID:
- ivo://CDS.VizieR/J/MNRAS/411/1597
- Title:
- LMC point source classification in SAGE-Spec
- Short Name:
- J/MNRAS/411/1597
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the classification of 197 point sources observed with the Infrared Spectrograph in the SAGE-Spec Legacy programme on the Spitzer Space Telescope. We introduce a decision-tree method of object classification based on infrared spectral features, continuum and spectral energy distribution shape, bolometric luminosity, cluster membership and variability information, which is used to classify the SAGE-Spec sample of point sources. The decision tree has a broad application to mid-infrared spectroscopic surveys, where supporting photometry and variability information are available. We use these classifications to make deductions about the stellar populations of the Large Magellanic Cloud and the success of photometric classification methods. We find 90 asymptotic giant branch (AGB) stars, 29 young stellar objects, 23 post-AGB objects, 19 red supergiants, eight stellar photospheres, seven background galaxies, seven planetary nebulae, two HII regions and 12 other objects, seven of which remain unclassified.
- ID:
- ivo://CDS.VizieR/J/A+A/405/111
- Title:
- LMC Survey of Young Stellar Systems
- Short Name:
- J/A+A/405/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The method developed by Gouliermis et al. (2000AJ....119.1737G), for the detection and classification of stellar systems in the LMC, was used for the identification of stellar associations and open clusters in the central area of the LMC. This method was applied on the stellar catalog produced from a scanned 1.2m UK Schmidt Telescope Plate in U with a field of view almost 6.5degx6.5deg, centered on the Bar of this galaxy. The survey of the identified systems is presented here followed by the results of the investigation on their spatial distribution and their structural parameters, as were estimated according to our proposed methodology. The detected open clusters and stellar associations show to form large filamentary structures, which are often connected with the loci of HI shells. The derived mean size of the stellar associations in this survey was found to agree with the average size found previously by other authors, for stellar associations in different galaxies. This common size of about 80pc might represent a universal scale for the star formation process, whereas the parameter correlations of the detected loose systems support the distinction between open clusters and stellar associations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/438/796
- Title:
- Local radio-galaxy population at 20GHz
- Short Name:
- J/MNRAS/438/796
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have made the first detailed study of the high-frequency radio-source population in the local Universe, using a sample of 202 radio sources from the Australia Telescope 20GHz (AT20G) survey identified with galaxies from the 6dF Galaxy Survey (6dFGS). The AT20G-6dFGS galaxies have a median redshift of z=0.058 and span a wide range in radio luminosity, allowing us to make the first measurement of the local radio luminosity function at 20GHz. Our sample includes some classical Fanaroff-Riley type I (FR I) and FR II radio galaxies, but most of the AT20G-6dFGS galaxies host compact (FR 0) radio active galactic nuclei which appear to lack extended radio emission even at lower frequencies. Most of these FR 0 sources show no evidence for relativistic beaming, and the FR 0 class appears to be a mixed population which includes young compact steep-spectrum and gigahertz peaked-spectrum radio galaxies. We see a strong dichotomy in the Wide-field Infrared Survey Explorer (WISE) mid-infrared colours of the host galaxies of FR I and FR II radio sources, with the FR I systems found almost exclusively in WISE 'early-type' galaxies and the FR II radio sources in WISE 'late-type' galaxies. The host galaxies of the flat- and steep-spectrum radio sources have a similar distribution in both K-band luminosity and WISE colours, though galaxies with flat-spectrum sources are more likely to show weak emission lines in their optical spectra. We conclude that these flat-spectrum and steep-spectrum radio sources mainly represent different stages in radio-galaxy evolution, rather than beamed and unbeamed radio-source populations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/2703
- Title:
- Local SDSS galaxies in Herschel Stripe 82
- Short Name:
- J/MNRAS/457/2703
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a set of 3319 galaxies in the redshift interval 0.04<z<0.15 Herschel/SPIRE 250{mu}m band. Total infrared (TIR) luminosities derived from HerS and Wide-field Infrared Survey Explorer (WISE) photometry allow us to compare infrared and optical estimates of SFR with unprecedented statistics for diverse classes of galaxies. We find excellent agreement between TIR-derived and emission line-based SFRs for H ii galaxies. Other classes, such as active galaxies and evolved galaxies, exhibit systematic discrepancies between optical and TIR SFRs. We demonstrate that these offsets are attributable primarily to survey biases and the large intrinsic uncertainties of the D_n_4000- and colour-based optical calibrations used to estimate the SDSS SFRs of these galaxies. Using a classification scheme which expands upon popular emission-line methods, we demonstrate that emission-line galaxies with uncertain classifications include a population of massive, dusty, metal-rich star-forming systems that are frequently neglected in existing studies. We also study the capabilities of infrared selection of star-forming galaxies. FIR selection reveals a substantial population of galaxies dominated by cold dust which are missed by the long-wavelength WISE bands. Our results demonstrate that Herschel large-area surveys offer the means to construct large, relatively complete samples of local star-forming galaxies with accurate estimates of SFR that can be used to study the interplay between nuclear activity and star formation.
