- ID:
- ivo://CDS.VizieR/II/305
- Title:
- SAGE LMC and SMC IRAC Source Catalog
- Short Name:
- II/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SAGE project is a Cycle 2 legacy program on the Spitzer Space Telescope, entitled, "Spitzer Survey of the Large Magellanic Cloud: Surveying the Agents of a Galaxy's Evolution (SAGE)", with Margaret Meixner (STScI) as the PI. The project overview and initial results are described in a paper by Meixner et al. (2006AJ....132.2268M). The Catalog is a highly reliable list of 6.4 million sources. Faint limits for SAGE are 18.1, 17.5, 15.3, and 14.2 for IRAC 3.6, 4.5, 5.8, 8.0 um, respectively. The SAGE-SMC project is a Cycle 4 legacy program on the Spitzer Space Telescope, entitled, "SAGE-SMC: Surveying the Agents of Galaxy Evolution in the Tidally-Disrupted, Low-Metallicity Small Magellanic Cloud", with Karl Gordon (STScI) as the PI. The project overview and initial results are described in a paper by Gordon et al. (2011AJ....142..102G). The Catalog is a highly reliable list of 2.0 million sources. Faint limits for SAGE-SMC are 18.3, 17.7, 15.7, and 14.5 for IRAC 3.6, 4.5, 5.8, 8.0 um, respectively. The archive tables are more complete but less reliable than the catalogs. IRAC Single Frame + Mosaic Photometry Catalog: a combination of mosaic photometry source list extracted from the combined Epoch 1 and Epoch 2 12 second frametime mosaics with all-epochs single frame source list, bandmerged with 2MASS or 2MASS6X. Detailed documentations are available from http://irsa.ipac.caltech.edu/data/SPITZER/SAGE/doc/ as SAGEDataProductsDescription_Sep09.pdf and from http://irsa.ipac.caltech.edu/data/SPITZER/SAGE-SMC/docs/ as sage-smc_delivery_apr11.pdf
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/470/3250
- Title:
- SAGE LMC point-sources classification
- Short Name:
- J/MNRAS/470/3250
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Infrared Spectrograph (IRS) on the Spitzer Space Telescope observed nearly 800 point sources in the Large Magellanic Cloud (LMC), taking over 1000 spectra. 197 of these targets were observed as part of the SAGE-Spec Spitzer Legacy program; the remainder are from a variety of different calibration, guaranteed time and open time projects. We classify these point sources into types according to their infrared spectral features, continuum and spectral energy distribution shape, bolometric luminosity, cluster membership and variability information, using a decision-tree classification method. We then refine the classification using supplementary information from the astrophysical literature. We find that our IRS sample is comprised substantially of YSO and HII regions, post-main-sequence low-mass stars: (post-)asymptotic giant branch stars and planetary nebulae and massive stars including several rare evolutionary types. Two supernova remnants, a nova and several background galaxies were also observed. We use these classifications to improve our understanding of the stellar populations in the LMC, study the composition and characteristics of dust species in a variety of LMC objects, and to verify the photometric classification methods used by mid-IR surveys. We discover that some widely used catalogues of objects contain considerable contamination and others are missing sources in our sample.
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/2814
- Title:
- SAGE SMC evolved stars candidates
- Short Name:
- J/MNRAS/457/2814
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The life cycle of dust in the interstellar medium is heavily influenced by outflows from asymptotic giant branch (AGB) and red supergiant (RSG) stars, a large fraction of which is contributed by a few very dusty sources. We compute the dust input to the Small Magellanic Cloud (SMC) by fitting the multi-epoch mid-infrared spectral energy distributions of AGB/RSG candidates with models from the Grid of RSG and AGB ModelS grid, allowing us to estimate the luminosities and dust-production rates (DPRs) of the entire population. By removing contaminants, we guarantee a high-quality data set with reliable DPRs and a complete inventory of the dustiest sources. We find a global AGB/RSG dust-injection rate of (1.3+/-0.1)x10^-6^M_{sun}_/yr, in agreement with estimates derived from mid-infrared colours and excess fluxes. As in the Large Magellanic Cloud, a majority (66 per cent) of the dust arises from the extreme AGB stars, which comprise only ~7 per cent of our sample. A handful of far-infrared sources, whose 24{mu}m fluxes exceed their 8{mu}m fluxes, dominate the dust input. Their inclusion boosts the global DPR by ~1.5x, making it necessary to determine whether they are AGB stars. Model assumptions, rather than missing data, are the major sources of uncertainty; depending on the choice of dust shell expansion speed and dust optical constants, the global DPR can be up to ~10 times higher. Our results suggest a non-stellar origin for the SMC dust, barring as yet undiscovered evolved stars with very high DPRs.
- ID:
- ivo://CDS.VizieR/J/ApJ/778/15
- Title:
- SAGE-SMC III. Young stellar objects
- Short Name:
- J/ApJ/778/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer Space Telescope Legacy Program SAGE-SMC allows global studies of resolved stellar populations in the SMC in a different environment than our Galaxy. Using the SAGE-SMC IRAC (3.6-8.0{mu}m) and MIPS (24 and 70{mu}m) catalogs and images combined with near-infrared (JHK_s_) and optical (UBVI) data, we identified a population of ~1000 intermediate - to high-mass young stellar objects (YSOs) in the SMC (three times more than previously known). Our method of identifying YSO candidates builds on the method developed for the Large Magellanic Cloud by Whitney et al. (2008, J/AJ/136/18) with improvements based on what we learned from our subsequent studies and techniques described in the literature. We perform (1) color-magnitude cuts based on five color-magnitude diagrams (CMDs), (2) visual inspection of multi-wavelength images, and (3) spectral energy distribution (SED) fitting with YSO models. For each YSO candidate, we use its photometry to calculate a measure of our confidence that the source is not a non-YSO contaminant, but rather a true YSO, based on the source's location in the color-magnitude space with respect to non-YSOs. We use this CMD score and the SED fitting results to define two classes of sources: high-reliability YSO candidates and possible YSO candidates. We found that, due to polycyclic aromatic hydrocarbon emission, about half of our sources have [3.6]-[4.5] and [4.5]-[5.8] colors not predicted by previous YSO models. The YSO candidates are spatially correlated with gas tracers.
- ID:
- ivo://CDS.VizieR/J/A+A/330/453
- Title:
- Sagittarius Dwarf Galaxy VI photometry
- Short Name:
- J/A+A/330/453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present V,I deep CCD photometry for three fields of the dwarf galaxy in Sagittarius (Sgr), located at l=5.6{deg}, b=-14.1{deg}. One of the fields is centered on the globular cluster NGC 6715 (M54), which lies in one of the dense clumps of the Sgr galaxy. Comparing the CMD of Sgr with those of globular clusters which are believed to be kinematically associated with the dwarf galaxy (Da Costa & Armandroff, 1995AJ....109.2533D), we conclude that the stellar population of Sgr presents a spread in metallicity of -0.71<=[Fe/H]<=-1.58, and that the dominant population (=~10Gyr old) is extremely similar to the star content of the associated globular cluster Terzan 7. The estimated distance to Sgr is d=~24.55Kpc.
- ID:
- ivo://CDS.VizieR/II/229
- Title:
- Sakurai's object (V4334 Sgr) in 1996-1998
- Short Name:
- II/229
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The photometric UBV observations of V4334 Sgr during 1996-1998 are presented. V4334 Sgr is the nucleus of a planetary nebula during the last helium flash of the shell source and it entered the R CrB phase.
- ID:
- ivo://CDS.VizieR/J/MNRAS/449/4010
- Title:
- SALT galaxy clusters detected by ACT
- Short Name:
- J/MNRAS/449/4010
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Southern African Large Telescope follow-up observations of seven massive clusters detected by the Atacama Cosmology Telescope (ACT) on the celestial equator using the Sunyaev-Zel'dovich (SZ) effect. We conducted multi-object spectroscopic observations with the Robert Stobie Spectrograph in order to measure galaxy redshifts in each cluster field, determine the cluster line-of-sight velocity dispersions, and infer the cluster dynamical masses. We find that the clusters, which span the redshift range 0.3<z<0.55, range in mass from (5-20)x10^14^M_{sun}_ (M_200c_). Their masses, given their SZ signals, are similar to those of Southern hemisphere ACT clusters previously observed using Gemini and the VLT. We note that the brightest cluster galaxy in one of the systems studied, ACT-CL J0320.4+0032 at z=0.38, hosts a type II quasar. Only a handful of such systems are currently known, and therefore ACT-CL J0320.4+0032 may be a rare example of a very massive halo in which quasar-mode feedback is actively taking place.
5758. SAMI Galaxy Survey: EDR
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/1567
- Title:
- SAMI Galaxy Survey: EDR
- Short Name:
- J/MNRAS/446/1567
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Early Data Release of the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. The SAMI Galaxy Survey is an ongoing integral field spectroscopic survey of ~3400 low-redshift (z<0.12) galaxies, covering galaxies in the field and in groups within the Galaxy And Mass Assembly (GAMA) survey regions, and a sample of galaxies in clusters. In the Early Data Release, we publicly release the fully calibrated data cubes for a representative selection of 107 galaxies drawn from the GAMA regions, along with information about these galaxies from the GAMA catalogues. All data cubes for the Early Data Release galaxies can be downloaded individually or as a set from the SAMI Galaxy Survey website. In this paper we also assess the quality of the pipeline used to reduce the SAMI data, giving metrics that quantify its performance at all stages in processing the raw data into calibrated data cubes. The pipeline gives excellent results throughout, with typical sky subtraction residuals in the continuum of 0.9-1.2 per cent, a relative flux calibration uncertainty of 4.1 per cent (systematic) plus 4.3 per cent (statistical), and atmospheric dispersion removed with an accuracy of 0.09-arcsec, less than a fifth of a spaxel.
- ID:
- ivo://CDS.VizieR/J/ApJ/804/7
- Title:
- SaMOSA: optical spectroscopy of 7 Fermi blazars
- Short Name:
- J/ApJ/804/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multi-epoch optical spectroscopy of seven southern Fermi-monitored blazars from 2008 to 2013 using the Small and Medium Aperture Research Telescope System (SMARTS), with supplemental spectroscopy and polarization data from the Steward Observatory. We find that the emission lines are much less variable than the continuum; four of seven blazars had no detectable emission line variability over the 5 yr observation period. This is consistent with photoionization primarily by an accretion disk, allowing us to use the lines as a probe of disk activity. Comparing optical emission line flux with Fermi {gamma}-ray flux and optical polarized flux, we investigate whether relativistic jet variability is related to the accretion flow. In general, we see no such dependence, suggesting that the jet variability is likely caused by internal processes like turbulence or shock acceleration rather than a variable accretion rate. However, three sources showed statistically significant emission line flares in close temporal proximity to very large Fermi {gamma}-ray flares. While we do not have sufficient emission line data to quantitatively assess their correlation with the {gamma}-ray flux, it appears that in some cases the jet might provide additional photoionizing flux to the broad-line region (BLR), which implies that some {gamma}-rays are produced within the BLR, at least for these large flares.
- ID:
- ivo://CDS.VizieR/J/ApJ/886/93
- Title:
- SAMP. III. Opt. LCs and spectra of two AGNs
- Short Name:
- J/ApJ/886/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Active galactic nuclei (AGNs) show a correlation between the size of the broad line region and the monochromatic continuum luminosity at 5100{AA}, allowing black hole mass estimation based on single-epoch spectra. However, the validity of the correlation is yet to be clearly tested for high-luminosity AGNs. We present the first reverberation mapping results of the Seoul National University AGN Monitoring Project (SAMP), which is designed to focus on luminous AGNs for probing the high end of the size-luminosity relation. We report time lag measurements of two AGNs, namely, 2MASSJ10261389+5237510 and SDSSJ161911.24+501109.2, using the light curves obtained over an ~1000d period with an average cadence of 10 and 20d, respectively, for photometry and spectroscopy monitoring. Based on a cross-correlation analysis and H{beta} line width measurements, we determine the H{beta} lag as 41.8_-6.0_^+4.9^ and 52.6_-14.7_^+17.6^ days in the observed frame, and black hole mass as 3.65_-0.57_^+0.49^x10^7^M_{sun}_ and 23.02_-6.56_^+7.81^x10^7^M_{sun}_, respectively, for 2MASS J1026 and SDSS J1619.
