- ID:
- ivo://CDS.VizieR/J/A+A/652/A76
- Title:
- Gaia Photometric Science Alerts
- Short Name:
- J/A+A/652/A76
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Since July 2014, the Gaia mission has been engaged in a high-spatial- resolution, time-resolved, precise, accurate astrometric, and photometric survey of the entire sky. We present the Gaia Science Alerts project, which has been in operation since 1 June 2016. We describe the system which has been developed to enable the discovery and publication of transient photometric events as seen by Gaia. We outline the data handling, timings, and performances, and we describe the transient detection algorithms and filtering procedures needed to manage the high false alarm rate. We identify two classes of events: (1) sources which are new to Gaia and (2) Gaia sources which have undergone a significant brightening or fading. Validation of the Gaia transit astrometry and photometry was performed, followed by testing of the source environment to minimise contamination from Solar System objects, bright stars, and fainter near-neighbours. We show that the Gaia Science Alerts project suffers from very low contamination, that is there are very few false- positives. We find that the external completeness for supernovae, C_E_=0.46, is dominated by the Gaia scanning law and the requirement of detections from both fields-of-view. Where we have two or more scans the internal completeness is C_I_=0.79 at 3 arcsec or larger from the centres of galaxies, but it drops closer in, especially within 1 arcsec. The per-transit photometry for Gaia transients is precise to 1 per cent at G=13, and 3 per cent at G=19. The per- transit astrometry is accurate to 55 milliarcseconds when compared to Gaia DR2. The Gaia Science Alerts project is one of the most homogeneous and productive transient surveys in operation, and it is the only survey which covers the whole sky at high spatial resolution (subarcsecond), including the Galactic plane and bulge.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/3411
- Title:
- Galactic SNR ^44^Ti survey
- Short Name:
- J/MNRAS/458/3411
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of the deepest Galactic plane (|b|<17.5{deg}) survey in the 67.9 and 78.4keV nuclear de-excitation lines of titanium-44 (^44^Ti) performed using the data acquired with the IBIS/ISGRI instrument onboard the INTEGRAL satellite during 12yr of operation. The peak sensitivity of our survey reached an unprecedented level of 4.8x10^-6^ph/cm2/s (3{sigma}) that improves the sensitivity of the survey done by Compton Gamma-Ray Observatory/COMPTEL by a factor of ~5. As a result, constraining upper limits for all sources from the catalogue of Galactic supernova remnants (SNRs; Green, 2014, Cat. VII/272) are derived. These upper limits can be used to estimate the exposure needed to detect ^44^Ti emission from any known SNR using existing and prospective X- and gamma-ray telescopes. Among the youngest Galactic SNRs, only Cas A shows significant ^44^Ti emission flux in good agreement with the NuSTAR measurements. We did not detect any other sources of titanium emission in the Galactic plane at significance level higher than 5{sigma} confirming previous claims of the rarity of such ^44^Ti-producing SNRs.
- ID:
- ivo://CDS.VizieR/II/205
- Title:
- GCVS, Vol. V.: Extragalactic Variable Stars
- Short Name:
- II/205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue is the last volume of the world-only reference source on all known variable stars. It contains the first Catalogue of variable stars in external galaxies as well as a Catalogue of extragalactic supernovae.
- ID:
- ivo://CDS.VizieR/J/ApJ/894/111
- Title:
- Gemini/GMOS-S spectra of the type IIn SN 2010jl
- Short Name:
- J/ApJ/894/111
- Date:
- 19 Jan 2022 13:05:54
- Publisher:
- CDS
- Description:
- The luminous Type IIn SN 2010jl shows strong signs of interaction between the SN ejecta and dense circumstellar material. Dust may be present in the unshocked ejecta; the cool, dense shell (CDS) between the shocks in the interaction region; or in the circumstellar medium (CSM). We present and model new optical and infrared photometry and spectroscopy of SN 2010jl from 82 to 1367 days since explosion. We evaluate the photometric and spectroscopic evolution using the radiative transfer codes MOCASSIN and DAMOCLES, respectively. We propose an interaction scenario and investigate the resulting dust formation scenarios and dust masses. We find that SN 2010jl has been continuously forming dust based on the evolution of its infrared emission and optical spectra. There is evidence for preexisting dust in the CSM as well as new dust formation in the CDS and/or ejecta. We estimate that 0.005-0.01M_{sun}_ of predominantly carbon dust grains has formed in SN 2010jl by ~1400 days post-outburst.
- ID:
- ivo://CDS.VizieR/J/ApJ/561/106
- Title:
- Gravitational lensing of SN 1997ff
- Short Name:
- J/ApJ/561/106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the effects of gravitational lensing due to intervening galaxies on the recently discovered Type Ia supernova at z~1.7, SN 1997ff, in the Hubble Deep Field North. We find that it is possible to obtain a wide range of magnifications by varying the mass and/or the velocity dispersion normalization of the lensing galaxies. In order to be able to use SN 1997ff to constrain the redshift-distance relation, very detailed modeling of the galaxies to control the systematic effects from lensing is necessary. Thus, we argue that, based on our current limited knowledge of the lensing galaxies, it is difficult to use SN 1997ff to constrain the values of {Omega}_M_ and {Omega}_{Lambda}, or even to place severe limits on gray dust obscuration or luminosity evolution of Type Ia supernovae.
- ID:
- ivo://CDS.VizieR/J/ApJ/774/114
- Title:
- GRB 081007 and GRB 090424 light curves
- Short Name:
- J/ApJ/774/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the results of the analysis of multi-wavelength data for the afterglows of GRB 081007 and GRB 090424, two bursts detected by Swift. One of them, GRB 081007, also shows a spectroscopically confirmed supernova, SN 2008hw, which resembles SN 1998bw in its absorption features, while the maximum magnitude may be fainter, up to 0.7mag, than observed in SN 1998bw. Bright optical flashes have been detected in both events, which allows us to derive solid constraints on the circumburst-matter density profile. This is particularly interesting in the case of GRB 081007, whose afterglow is found to be propagating into a constant-density medium, yielding yet another example of a gamma-ray burst (GRB) clearly associated with a massive-star progenitor which did not sculpt the surroundings with its stellar wind. There is no supernova component detected in the afterglow of GRB 090424, likely due to the brightness of the host galaxy, comparable to the Milky Way. We show that the afterglow data are consistent with the presence of both forward- and reverse-shock emission powered by relativistic outflows expanding into the interstellar medium. The absence of optical peaks due to the forward shock strongly suggests that the reverse-shock regions should be mildly magnetized. The initial Lorentz factor of outflow of GRB 081007 is estimated to be {Gamma}~200, while for GRB 090424 a lower limit of {Gamma}>170 is derived. We also discuss the prompt emission of GRB 081007, which consists of just a single pulse. We argue that neither the external forward-shock model nor the shock-breakout model can account for the prompt emission data and suggest that the single-pulse-like prompt emission may be due to magnetic energy dissipation of a Poynting-flux-dominated outflow or to a dissipative photosphere.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A50
- Title:
- GRB 190829A/SN 2019oyw spectra
- Short Name:
- J/A+A/646/A50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gamma-ray burst (GRB) 190829A (z=0.0785) was detected by Fermi and Swift and also at very high energy (VHE) by the High-Energy Stereoscopic System (H.E.S.S.) telescopes. The prompt emission displayed two emission episodes separated by a quiescent gap of ~40s. We present the 10.4m Gran Telescopio CANARIAS (GTC) observations of the afterglow of GRB 190829A and its underlying supernova. We also compare GRB190829A to GRB180728A, a GRB with similar behaviour, and discuss the implications on underlying physical mechanisms producing these two GRBs. We present multi-band photometric data along with spectroscopic follow-up observations taken with the 10.4m GTC telescope. Together with the data from the prompt emission, the 10.4m GTC data are used to understand the emission mechanisms and possible progenitor. A detailed analysis of the multi-band observations of the afterglow requires the cooling frequency to pass between the optical and X-ray bands at early epochs. The afterglow then transitions to the underlying supernova (SN) 2019oyw, which dominates later on. Although the prompt emission temporal properties of GRB 190829A and GRB 180728A are similar, the two pulses are different in the spectral domain. We find that SN 2019oyw associated with GRB 190829A is powered by Ni decay and is a Type Ic-BL SN. The spectroscopic and photometric properties of this SN are consistent with those observed for SN 1998bw, but evolved earlier.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A39
- Title:
- GRB190114C spectra and light curves
- Short Name:
- J/A+A/659/A39
- Date:
- 01 Mar 2022 09:36:26
- Publisher:
- CDS
- Description:
- We observed GRB190114C (redshift z=0.4245), the first gamma-ray burst (GRB) ever detected at TeV energies, at optical and near-infrared wavelengths with several ground-based telescopes and the Hubble Space Telescope, with the primary goal of studying its underlying supernova, SN 2019jrj. The monitoring spanned the time interval between 1.3 and 370 days after the burst, in the observer frame. We find that the afterglow emission can be modelled with a forward shock propagating in a uniform medium modified by time-variable extinction along the line of sight. A jet break could be present after 7 rest-frame days, and accordingly the maximum luminosity of the underlying supernova (SN) ranges between that of stripped-envelope core-collapse SNe of intermediate luminosity and that of the luminous GRB-associated SN 2013dx. The observed spectral absorption lines of SN 2019jrj are not as broad as in classical GRB SNe and are instead more similar to those of less-luminous core-collapse SNe. Taking the broad-lined stripped-envelope core-collapse SN 2004aw as an analogue, we tentatively derive the basic physical properties of SN 2019jrj. We discuss the possibility that a fraction of the TeV emission of this source might have had a hadronic origin and estimate the expected high-energy neutrino detection level with IceCube.
- ID:
- ivo://CDS.VizieR/J/AJ/130/2453
- Title:
- 9 high-redshift ESSENCE supernovae
- Short Name:
- J/AJ/130/2453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present broadband light curves of nine supernovae ranging in redshift from 0.5 to 0.8. The supernovae were discovered as part of the ESSENCE project, and the light curves are a combination of Cerro Tololo 4m and Hubble Space Telescope (HST) photometry. On the basis of spectra and/or light-curve fitting, eight of these objects are definitely Type Ia supernovae, while the classification of one is problematic. The ESSENCE project is a 5yr endeavor to discover about 200 high-redshift Type Ia supernovae, with the goal of tightly constraining the time average of the equation-of-state parameter [w=p/({rho}c^2^)] of the "dark energy." To help minimize our systematic errors, all of our ground-based photometry is obtained with the same telescope and instrument. In 2003 the highest redshift subset of ESSENCE supernovae was selected for detailed study with HST. Here we present the first photometric results of the survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/602/571
- Title:
- High-redshift supernovae IRZ fluxes
- Short Name:
- J/ApJ/602/571
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric and spectroscopic observations of 23 high-redshift supernovae (SNe) spanning a range of z=0.34-1.03, nine of which are unambiguously classified as Type Ia. These SNe were discovered during the IfA Deep Survey, which began in 2001 September and observed a total of 2.5deg^2^ to a depth of approximately m~25-26 in RIZ over 9-17 visits, typically every 1-3 weeks for nearly 5 months, with additional observations continuing until 2002 April.
