- ID:
- ivo://CDS.VizieR/J/ApJS/201/10
- Title:
- SDSS quasar catalog with Swift observations
- Short Name:
- J/ApJS/201/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a catalog of optically selected quasars with simultaneous observations in UV/optical and X-ray bands by the Swift Gamma-ray Burst Explorer. Objects in this catalog are identified by matching the Swift pointings with the Sloan Digital Sky Survey Data Release 5 quasar catalog. The final catalog contains 843 objects, among which 637 have both Ultraviolet Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations and 354 of which are detected by both instruments. The overall X-ray detection rate is ~60% which rises to ~85% among sources with at least 10ks of XRT exposure time. We construct the time-averaged spectral energy distribution (SED) for each of the 354 quasars using UVOT photometric measurements and XRT spectra. From model fits to these SEDs, we find that the big blue bump contributes about ~0.3 dex to the quasar luminosity. We re-visit the {alpha}_ox_-L_2500_{AA} relation by selecting a clean sample with only Type 1 radio-quiet quasars; the dispersion of this relation is reduced by at least 15% compared with studies that use non-simultaneous UV/optical and X-ray data.
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- ID:
- ivo://CDS.VizieR/J/A+A/561/A33
- Title:
- SDSS star-forming galaxies multi-wavelength study
- Short Name:
- J/A+A/561/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied a large sample of ~14000 dwarf star-forming galaxies with strong emission lines. These low-metallicity galaxies with oxygen abundances of 12+logO/H~7.4-8.5 are selected from the Sloan Digital Sky Survey (SDSS) and distributed in the redshift range of z~0-0.6. We modelled spectral energy distributions (SED) of all galaxies, which were based on the SDSS spectra in the visible range of 0.38{mu}m-0.92{mu}m and included both the stellar and ionised gas emission. These SEDs were extrapolated to the UV and mid-infrared ranges to cover the wavelength range of 0.1{mu}m-22{mu}m. The SDSS spectroscopic data were supplemented by photometric data from the GALEX, SDSS, 2MASS, WISE, IRAS, and NVSS all-sky surveys. Using these data, we derived global characteristics of the galaxies, such as their element abundances, luminosities, and stellar masses.
- ID:
- ivo://CDS.VizieR/J/ApJ/896/1
- Title:
- SEAMBHs. XI. Mrk 142 X-ray to optical light curves
- Short Name:
- J/ApJ/896/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed an intensive accretion disk reverberation mapping campaign on the high accretion rate active galactic nucleus Mrk142 in early 2019. Mrk 142 was monitored with the Neil Gehrels Swift Observatory for four months in X-rays and six different UV/optical filters. Ground-based photometric monitoring was obtained from the Las Cumbres Observatory, the Liverpool Telescope, and the Dan Zowada Memorial Observatory in ugriz filters, as well as from the Yunnan Astronomical Observatory in V. Mrk 142 was highly variable throughout, displaying correlated variability across all wavelengths. We measure significant time lags between the different wavelength lightcurves. In the UV and optical, we find that the wavelength-dependent lags, {tau}({lambda}), generally follow the relation {tau}({lambda}){propto}{lambda}^4/3^, as expected for the T{propto}R^-3/4^ profile of a steady-state, optically thick, geometrically thin accretion disk, though they can also be fit by {tau}({lambda}){propto}{lambda}^2^, as expected for a slim disk. The exceptions are the u and U bands, where an excess lag is observed, as has been observed in other active galactic nuclei and attributed to continuum emission arising in the broad-line region. Furthermore, we perform a flux-flux analysis to separate the constant and variable components of the spectral energy distribution, finding that the flux dependence of the variable component is consistent with the f{nu}{propto}{nu}^1/3^ spectrum expected for a geometrically thin accretion disk. Moreover, the X-ray to UV lag is significantly offset from an extrapolation of the UV/optical trend, with the X-rays showing a poorer correlation with the UV than the UV does with the optical. The magnitude of the UV/optical lags is consistent with a highly super-Eddington accretion rate.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A140
- Title:
- SEDs of M33 HII regions
- Short Name:
- J/A+A/552/A140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Within the framework of the Herschel M33 extended survey HerM33es and in combination with multi-wavelength data we study the spectral energy distribution (SED) of a set of HII regions in the Local Group galaxy M33 as a function of the morphology. We analyse the emission distribution in regions with different morphologies and present models to infer the H{alpha} emission measure observed for HII regions with well defined morphology. We present a catalogue of 119 HII regions morphologically classified: 9 filled, 47 mixed, 36 shell, and 27 clear shell HII regions. For each object we extracted the photometry at twelve available wavelength bands, covering a wide wavelength range from FUV-1516{AA} (GALEX) to IR-250um (Herschel), and we obtained the SED for each object. We also obtained emission line profiles in vertical and horizontal directions across the regions to study the location of the stellar, ionised gas, and dust components. We constructed a simple geometrical model for the clear shell regions, whose properties allowed us to infer the electron density of these regions.
- ID:
- ivo://CDS.VizieR/J/ApJ/759/6
- Title:
- SEDs of type I AGN in COSMOS. I. XMM-COSMOS
- Short Name:
- J/ApJ/759/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The "Cosmic Evolution Survey" (COSMOS) enables the study of the spectral energy distributions (SEDs) of active galactic nuclei (AGNs) because of the deep coverage and rich sampling of frequencies from X-ray to radio. Here we present an SED catalog of 413 X-ray (XMM-Newton)-selected type 1 (emission line FWHM>2000km/s) AGNs with Magellan, SDSS, or VLT spectrum. The SEDs are corrected for Galactic extinction, broad emission line contributions, constrained variability, and host galaxy contribution. We present the mean SED and the dispersion SEDs after the above corrections in the rest-frame 1.4GHz to 40keV, and show examples of the variety of SEDs encountered. In the near-infrared to optical (rest frame ~8{mu}m-4000{AA}), the photometry is complete for the whole sample and the mean SED is derived from detections only. Reddening and host galaxy contamination could account for a large fraction of the observed SED variety.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A136
- Title:
- SN 2020bqj ligth curves
- Short Name:
- J/A+A/652/A136
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Type Ibn supernovae are a rare class of stripped envelope supernovae interacting with a helium-rich CSM. The majority of the SNe Ibn reported display a surprising homogeneity in their fast lightcurves and starforming hosts. We present the discovery and study of SN 2020bqj (ZTF20aalrqbu), a SN Ibn with a long-duration peak plateau lasting 40 days and hosted by a faint low-mass galaxy. We aim to explain its peculiar properties using an extensive data set. We compare the evolution of SN 2020bqj with SNe Ibn from the literature. We fit the bolometric and multi-band lightcurves with different powering mechanism models. The risetime, peak magnitude and spectral features of SN 2020bqj are consistent with those of most SNe Ibn, but the SN is a clear outlier based on its bright, long-lasting peak plateau and low host mass. We show through modeling that the lightcurve can be powered predominantly by shock heating from the interaction of the SN ejecta and a dense CSM. The peculiar Type Ibn SN 2011hw is a close analog to SN 2020bqj, suggesting a similar progenitor and CSM scenario. In this scenario a very massive progenitor star in the transitional phase between a luminous blue variable and a compact Wolf-Rayet star undergoes core-collapse, embedded in a dense helium-rich CSM with an elevated opacity compared to normal SNe Ibn, due to the presence of residual hydrogen. This scenario is consistent with the observed properties of SN 2020bqj and the modeling results. SN 2020bqj is a compelling example of a transitional SN Ibn/IIn based on not only its spectral features, but also its lightcurve, host galaxy properties and the inferred progenitor properties. The strong similarity with SN 2011hw suggests this subclass may be the result of a progenitor in a stellar evolution phase that is distinct from those of progenitors of regular SNe Ibn.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A22
- Title:
- SN 2020faa multiphotometry and spectra
- Short Name:
- J/A+A/646/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of SN 2020faa. This Type II supernova displays a luminous lightcurve that started to rebrighten from an initial decline. We investigate this in relation to the famous supernova iPTF14hls, which received a great deal of attention and multiple interpretations in the literature, but whose nature and source of energy still remain unknown. We demonstrate the great similarity between SN 2020faa and iPTF14hls during the first 6 months, and use this comparison to forecast the evolution of SN 2020faa and to reflect on the less well observed early evolution of iPTF14hls. We present and analyse our observational data, consisting mainly of optical lightcurves from the Zwicky Transient Facility in the gri bands and of a sequence of optical spectra. We construct colour curves and a bolometric lightcurve, and we compare ejecta-velocity and black-body radius evolutions for the two supernovae and for more typical Type II supernovae. The lightcurves show a great similarity with those of iPTF14hls over the first 6 months in luminosity, timescale, and colour. In addition, the spectral evolution of SN 2020faa is that of a Type II supernova, although it probes earlier epochs than those available for iPTF14hls. The similar lightcurve behaviour is suggestive of SN 2020faa being a new iPTF14hls. We present these observations now to advocate follow-up observations, since most of the more striking evolution of supernova iPTF14hls came later, with lightcurve undulations and a spectacular longevity. On the other hand, for SN 2020faa we have better constraints on the explosion epoch than we had for iPTF14hls, and we have been able to spectroscopically monitor it from earlier phases than was done for the more famous sibling.
- ID:
- ivo://CDS.VizieR/J/ApJ/882/L15
- Title:
- SN 2018hna photometry & spectroscopy obs.
- Short Name:
- J/ApJ/882/L15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-cadence ultraviolet, optical, and near-infrared photometric and low-resolution spectroscopic observations of the peculiar Type II supernova (SN) 2018hna are presented. The early-phase multiband light curves (LCs) exhibit the adiabatic cooling envelope emission following the shock breakout up to ~14 days from the explosion. SN 2018hna has a rise time of ~88 days in the V band, similar to SN 1987A. A ^56^Ni mass of ~0.087+/-0.004M_{sun}_ is inferred for SN 2018hna from its bolometric LC. Hydrodynamical modeling of the cooling phase suggests a progenitor with a radius ~50R_{sun}_, a mass of ~14-20M_{sun}_, and an explosion energy of ~1.7-2.9x10^51^erg. The smaller inferred radius of the progenitor than a standard red supergiant is indicative of a blue supergiant progenitor of SN 2018hna. A subsolar metallicity (~0.3Z_{sun}_) is inferred for the host galaxy UGC 07534, concurrent with the low-metallicity environments of 1987A-like events.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/39
- Title:
- SN Ibn PS1-12sk optical and NIR light curves
- Short Name:
- J/ApJ/769/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on our discovery and observations of the Pan-STARRS1 supernova (SN) PS1-12sk, a transient with properties that indicate atypical star formation in its host galaxy cluster or pose a challenge to popular progenitor system models for this class of explosion. The optical spectra of PS1-12sk classify it as a Type Ibn SN (SN Ibn; cf. SN 2006jc), dominated by intermediate-width (3x10^3^km/s) and time variable He I emission. Our multi-wavelength monitoring establishes the rise time dt ~9-23 days and shows an NUV-NIR spectral energy distribution with temperature >~17x10^3^K and a peak magnitude of M_z_=-18.88+/-0.02mag. SN Ibn spectroscopic properties are commonly interpreted as the signature of a massive star (17-100M_{sun}_) explosion within an He-enriched circumstellar medium. However, unlike previous SNe Ibn, PS1-12sk is associated with an elliptical brightest cluster galaxy, CGCG 208-042 (z=0.054) in cluster RXC J0844.9+4258. The expected probability of an event like PS1-12sk in such environments is low given the measured infrequency of core-collapse SNe in red-sequence galaxies compounded by the low volumetric rate of SN Ibn. Furthermore, we find no evidence of star formation at the explosion site to sensitive limits ({Sigma}_H{alpha}_<~2x10^-3^M_{sun}_/yr/kpc2). We therefore discuss white dwarf binary systems as a possible progenitor channel for SNe Ibn. We conclude that PS1-12sk represents either a fortuitous and statistically unlikely discovery, evidence for a top-heavy initial mass function in galaxy cluster cooling flow filaments, or the first clue suggesting an alternate progenitor channel for SNe Ibn.
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/1312
- Title:
- SN2009ip UBVRI, UVOT and JHK light curves
- Short Name:
- J/MNRAS/433/1312
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ultraviolet, optical and near-infrared observations of the interacting transient SN 2009ip, covering the period from the start of the outburst in 2012 October until the end of the 2012 observing season. The transient reached a peak magnitude of M_V_=-17.7mag, with a total integrated luminosity of 1.9x10^49^erg over the period of 2012 August-December. The light curve fades rapidly, dropping by 4.5mag from the V-band peak in 100d. The optical and near-infrared spectra are dominated by narrow emission lines with broad electron scattering wings, signalling a dense circumstellar environment, together with multiple components of broad emission and absorption in H and He at velocities in the range 0.5-1.2x10^4^km/s. We see no evidence for nucleosynthesized material in SN 2009ip, even in late-time pseudo-nebular spectra. We set a limit of <0.02M_{sun}_ on the mass of any possible synthesized 56Ni from the late-time light curve. A simple model for the narrow Balmer lines is presented and used to derive number densities for the circumstellar medium in the range ~10^9^-10^10^cm^-3^. Our near-infrared data do not show any excess at longer wavelengths, and we see no other signs of dust formation. Our last data, taken in 2012 December, show that SN 2009ip has spectroscopically evolved to something quite similar to its appearance in late 2009, albeit with higher velocities. It is possible that neither of the eruptive and high-luminosity events of SN 2009ip were induced by a core collapse. We show that the peak and total integrated luminosity can be due to the efficient conversion of kinetic energy from colliding ejecta, and that around 0.05-0.1M_{sun}_ of material moving at 0.5-1x10^4^km/s could comfortably produce the observed luminosity. We discuss the possibility that these shells were ejected by the pulsational pair instability mechanism, in which case the progenitor star may still exist, and will be observed after the current outburst fades. The long-term monitoring of SN 2009ip, due to its proximity, has given the most extensive data set yet gathered of a high-luminosity interacting transient and its progenitor. It is possible that some purported Type IIn supernovae are in fact analogues of the 2012b event and that pre-explosion outbursts have gone undetected.