- ID:
- ivo://CDS.VizieR/J/MNRAS/473/4731
- Title:
- Barred galaxies structural decomposition
- Short Name:
- J/MNRAS/473/4731
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of two-component (disc+bar) and three-component (disc+bar+bulge) multiwavelength 2D photometric decompositions of barred galaxies in five Sloan Digital Sky Survey (SDSS) bands (ugriz). This sample of ~3500 nearby (z<0.06) galaxies with strong bars selected from the Galaxy Zoo citizen science project is the largest sample of barred galaxies to be studied using photometric decompositions that include a bar component. With detailed structural analysis, we obtain physical quantities such as the bar- and bulge-to-total luminosity ratios, effective radii, Sersic indices and colours of the individual components. We observe a clear difference in the colours of the components, the discs being bluer than the bars and bulges. An overwhelming fraction of bulge components have Sersic indices consistent with being pseudo-bulges. By comparing the barred galaxies with a mass-matched and volume-limited sample of unbarred galaxies, we examine the connection between the presence of a large-scale galactic bar and the properties of discs and bulges. We find that the discs of unbarred galaxies are significantly bluer compared to the discs of barred galaxies, while there is no significant difference in the colours of the bulges. We find possible evidence of secular evolution via bars that leads to the build-up of pseudo-bulges and to the quenching of star formation in the discs. We identify a subsample of unbarred galaxies with an inner lens/oval and find that their properties are similar to barred galaxies, consistent with an evolutionary scenario in which bars dissolve into lenses. This scenario deserves further investigation through both theoretical and observational work.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/1749
- Title:
- Barred S0 galaxies in the Coma cluster
- Short Name:
- J/MNRAS/439/1749
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study uses r-band images from the Eighth Data Release of the Sloan Digital Sky Survey (SDSS DR8) to study bars in lenticular (S0) galaxies in one of the nearest rich cluster environments, the Coma cluster. We develop techniques for bar detection and assess their success when applied to SDSS image data. To detect and characterize bars, we perform 2D bulge+disc+bar light decompositions of galaxy images with galfit. Using a sample of artificial galaxy images, we determine the faintest magnitude at which bars can be successfully measured at the depth and resolution of SDSS. We perform detailed decompositions of 83 S0 galaxies in Coma, 64 from a central sample, and 19 from a cluster outskirt sample. For the central sample, the S0 bar fraction is 72^+5^_-6_%. This value is significantly higher than that obtained using an ellipse-fitting method for bar detection, 48^+6^_-6_%. At a fixed luminosity, barred S0s are redder in g-r colour than unbarred S0s by 0.02mag. The frequency and strength of bars increase towards fainter luminosities. Neither central metallicity nor stellar age distributions differ significantly between barred and unbarred S0s. There is an increase in the bar fraction towards the cluster core, but this is at a low significance level. Bars have at most a weak correlation with cluster-centric radius.
- ID:
- ivo://CDS.VizieR/J/ApJ/870/31
- Title:
- BAT AGN spectroscopic survey. XI. IR photometry
- Short Name:
- J/ApJ/870/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We quantify the luminosity contribution of active galactic nuclei (AGNs) to the 12{mu}m, mid-infrared (MIR; 5-38{mu}m), and total IR (5-1000{mu}m) emission in the local AGNs detected in the all-sky 70 month Swift/Burst Alert Telescope (BAT) ultrahard X-ray survey. We decompose the IR spectral energy distributions (SEDs) of 587 objects into the AGN and starburst components using templates for an AGN torus and a star-forming galaxy. This enables us to recover the emission from the AGN torus including the low-luminosity end, down to log(L_14-150_/erg/s)~41, which typically has significant host galaxy contamination. The sample demonstrates that the luminosity contribution of the AGN to the 12{mu}m, the MIR, and the total IR bands is an increasing function of the 14-150keV luminosity. We also find that for the most extreme cases, the IR pure-AGN emission from the torus can extend up to 90{mu}m. The total IR AGN luminosity obtained through the IR SED decomposition enables us to estimate the fraction of the sky obscured by dust, i.e., the dust covering factor. We demonstrate that the median dust covering factor is always smaller than the median X-ray obscuration fraction above an AGN bolometric luminosity of log(L_bol_^(AGN)^/erg/s)~42.5. Considering that the X-ray obscuration fraction is equivalent to the covering factor coming from both the dust and gas, this indicates that an additional neutral gas component, along with the dusty torus, is responsible for the absorption of X-ray emission.
- ID:
- ivo://CDS.VizieR/J/AJ/141/99
- Title:
- BATC and SDSS photometry of A2589 cluster
- Short Name:
- J/AJ/141/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Smooth X-ray morphology and non-detection of a radio source at the center of A2589 indicate that it is a typical case of a well-relaxed regular galaxy cluster. In this paper, we present a multicolor photometry for A2589 (z=0.0414) with 15 intermediate bands in the Beijing-Arizona-Taiwan-Connecticut (BATC) system which covers an optical wavelength range from 3000{AA} to 10000{AA}. The spectral energy distributions (SEDs) for more than 5000 sources are achieved down to V~20mag in about a 1{deg}^2^ field. A2589 has also been covered by the Sloan Digital Sky Survey (SDSS) in photometric mode only. A cross-identification of the BATC-detected galaxies with the SDSS photometric catalog yields 1199 galaxies brighter than i=19.5mag, among which 68 member galaxies with known spectroscopic redshifts are found. After combining the SDSS five-band photometric data and the BATC SEDs, photometric redshift is applied to these galaxies to select faint member galaxies. The color-magnitude relation is taken as a further restriction of early-type cluster galaxies. As a result, 106 galaxies are newly selected as member galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/148/110
- Title:
- BATC ceimo light curves of 1ES 0806+52.4
- Short Name:
- J/AJ/148/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the first systematic long-term multicolor optical monitoring of the BL Lacertae object 1ES 0806+52.4. The monitoring was performed in multiple passbands with a 60/90cm Schmidt telescope from 2005 December to 2011 February. The overall brightness of this object decreased from 2005 December to 2008 December but was regained after that. A sharp outburst probably occurred around the end of our monitoring program. Overlapping the long-term trend are some short-term small-amplitude oscillations. No intranight variability was found in the object, which is in accordance with the historical observations before 2005. By investigating the color behavior, we found a strong bluer-when-brighter chromatism for the long-term variability of 1ES 0806+52.4. The total amplitudes at the c, i, and o bands are 1.18, 1.12, and 1.02mag, respectively. The amplitudes tend to increase toward shorter wavelengths, which may be a major cause of the bluer-when-brighter chromatism. Such bluer-when-brighter chromatisms are also found in other blazars, such as S5 0716+714, OJ 287. The hard-X-ray data collected from the Swift/BAT archive was correlated with our optical data. No positive result was found, the reason for which may be that the hard-X-ray flux is a combination of the synchrotron and inverse Compton emission, but with different timescales and cadences under the leptonic synchrotron self-Compton model.
- ID:
- ivo://CDS.VizieR/J/AJ/141/65
- Title:
- BATC ceimo light curves of OJ 287
- Short Name:
- J/AJ/141/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper studies the color behavior of the BL Lac object OJ 287 during an optical outburst. Upon revisiting the data from the OJ 94 monitoring project, and from an analysis of the data obtained with the 60/90cm Schmidt Telescope of NAOC, we found a bluer-when-brighter chromatism in this object. The amplitude of variation tends to decrease with frequency. These results are consistent with the shock-in-jet model. We ran some simulations and confirmed that both amplitude difference and time delay between variations at different wavelengths can result in the bluer-when-brighter phenomenon. Our observations confirmed that OJ 287 underwent a double-peaked outburst about 12 years after 1996, which provides further evidence for the binary black hole model in this object.
- ID:
- ivo://CDS.VizieR/II/262
- Title:
- BATC Data Release One - BATC DR1
- Short Name:
- II/262
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Multi-color photometry data of the project, "Large Field Multi-Color Sky Survey" supported by Beijing-Arizona-Taiwan-Connecticut (BATC) is presented. From 1995 to 2004, 110 58'x58' sky survey fields have been observed. First release of BATC catalog includes observation results for 511842 sources located in 70 sky survey fields. The whole release is divided into 70 files. Each file corresponds to one observation field. The BATC filter system includes 15 intermediate band filters, covering a range in optical wavelengths from 300 to 1000 nm. The telescope used is a 60/90 cm f/3 Schmidt telescope located at Xinglong Station of National Astronomical Observatories. A Ford Aerospace 2048x2048 CCD camera with 15 micron pixel size is mounted at the Schmidt focus of the telescope. The field of view of the CCD is 58'x58' with a plate scale of 1.7arcsec per pixel. The BATC magnitude system adopts the AB magnitude system, defining as M_batc_ = -2.5log(F_{nu}_) - 48.60 where F_{nu}_ is the flux per unit frequency in units of erg/s/cm^2^/Hz, and F_{nu}_={Sum}[d(log{nu})*f_{nu}_*R_{nu}_]/{Sum}[d(log{nu})*R_{nu}_] where R_{nu}_ represents the response of the system. Four Oke & Gunn (1983ApJ...266..713O) standards, HD 19445, HD 84937, BD+26 2606 and BD+17 4708 are observed in photometric nights for flux calibration. We provide catalogues down to i-band (666nm) about 20 mag with complete spectral energy distributions (SEDs) for each object. Typical error in photometry is about 0.02-0.05 mag. There is usually the deepest observation at i-band. Most of the catalogs use i-band data as their reference for coordinate calibration. While, "T0329","TA01" and "TA03" use j-band as reference. All colors in the "TA04" catalog have no photo calibration. For detailed information of the data reduction, please refer to: Zhou, X., Jiang, Z., Ma, J., et al. 2003, 2003A&A...397..361Z
- ID:
- ivo://CDS.VizieR/J/MNRAS/373/209
- Title:
- BATC eim photometry of BL Lac
- Short Name:
- J/MNRAS/373/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of our observations is to investigate the intra-night variability properties and the spectral variability of BL Lacertae. 799 optical multiband observations were intensively made with the Beijing-Arizona-Taiwan-Connecticut (BATC) 60/90cm Schmidt telescope during the outburst composed of two subsequent flares in 2005. The second flare, whose rising phase lasted at least 44d, was observed with amplitudes of more than 1.1mag in three BATC optical bands. In general, on intra-night time-scale the amplitude of variability and the variation rate are larger at the shorter wavelength, and the variation rate is comparable in the rising and decaying phases within each band. A possible time-lag between the light curves in bands e and m, around 11.6min, was obtained. Based on the analysis of the colour index variation with the source brightness, the variability of BL Lacertae can be interpreted as having two components: a 'strongly chromatic' intra-night component and a 'mildly chromatic' inter-night component, which may be the results of both intrinsic physical mechanism and geometric effects.
- ID:
- ivo://CDS.VizieR/J/other/RAA/10.1
- Title:
- BATC photometry in A98 cluster
- Short Name:
- J/other/RAA/10.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An optical photometric observation with the Beijing-Arizona-Taiwan-Connecticut (BATC) multicolor system is carried out for A98 (z=0.104), a galaxy cluster with two large enhancements in X-ray surface brightness. Spectral energy distributions (SEDs) covering 15 intermediate bands are obtained for all sources detected down to V~20mag in a field of 58'x58'. After star-galaxy separation with color-color diagrams, a photometric redshift technique is applied to the galaxy sample for further membership determination. The color-magnitude relation is taken as a further restriction of the early-type cluster galaxies. As a result, a list of 198 faint member galaxies is achieved. Based
- ID:
- ivo://CDS.VizieR/J/AJ/131/2245
- Title:
- BATC photometry of SN2004dj
- Short Name:
- J/AJ/131/2245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric data of the Type II-P supernova (SN) 2004dj in NGC 2403. The multicolor light curves cover the SN from 60 to 200 days after explosion and are measured with a set of intermediate-band filters that have the advantage of tracing the strength variations of some spectral features.
