- ID:
- ivo://CDS.VizieR/J/ApJS/185/32
- Title:
- First-year SDSS-II SN results
- Short Name:
- J/ApJS/185/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present measurements of the Hubble diagram for 103 Type Ia supernovae (SNe) with redshifts 0.04<z<0.42, discovered during the first season (Fall 2005) of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. These data fill in the redshift "desert" between low- and high-redshift SN Ia surveys. Within the framework of the MLCS2K2 light-curve fitting method, we use the SDSS-II SN sample to infer the mean reddening parameter for host galaxies, R_V_=2.18+/-0.14_stat_+/-0.48_syst_, and find that the intrinsic distribution of host-galaxy extinction is well fitted by an exponential function, P(A_V_)=exp(-A_V_/{tau}_V_), with {tau}_V_=0.334+/-0.088mag. We combine the SDSS-II measurements with new distance estimates for published SN data from the ESSENCE survey, the Supernova Legacy Survey (SNLS), the Hubble Space Telescope (HST), and a compilation of Nearby SN Ia measurements. A new feature in our analysis is the use of detailed Monte Carlo simulations of all surveys to account for selection biases, including those from spectroscopic targeting.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/890/131
- Title:
- Follow-up of candidate counterparts of S190814bv
- Short Name:
- J/ApJ/890/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On 2019 August 14, the Advanced LIGO and Virgo interferometers detected the high-significance gravitational wave (GW) signal S190814bv. The GW data indicated that the event resulted from a neutron star-black hole (NSBH) merger, or potentially a low-mass binary BH merger. Due to the low false-alarm rate and the precise localization (23deg^2^ at 90%), S190814bv presented the community with the best opportunity yet to directly observe an optical/near-infrared counterpart to an NSBH merger. To search for potential counterparts, the GROWTH Collaboration performed real-time image subtraction on six nights of public Dark Energy Camera images acquired in the 3 weeks following the merger, covering >98% of the localization probability. Using a worldwide network of follow-up facilities, we systematically undertook spectroscopy and imaging of optical counterpart candidates. Combining these data with a photometric redshift catalog, we ruled out each candidate as the counterpart to S190814bv and placed deep, uniform limits on the optical emission associated with S190814bv. For the nearest consistent GW distance, radiative transfer simulations of NSBH mergers constrain the ejecta mass of S190814bv to be M_ej_<0.04M_{sun}_ at polar viewing angles, or M_ej_<0.03M_{sun}_ if the opacity is {kappa}<2cm^2^g^-1^. Assuming a tidal deformability for the NS at the high end of the range compatible with GW170817 results, our limits would constrain the BH spin component aligned with the orbital momentum to be {chi}<0.7 for mass ratios Q<6, with weaker constraints for more compact NSs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/475/193
- Title:
- Foundation Supernova Survey first data release
- Short Name:
- J/MNRAS/475/193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Foundation Supernova Survey aims to provide a large, high-fidelity, homogeneous, and precisely calibrated low-redshift Type Ia supernova (SN Ia) sample for cosmology. The calibration of the current low-redshift SN sample is the largest component of systematic uncertainties for SN cosmology, and new data are necessary to make progress. We present the motivation, survey design, observation strategy, implementation, and first results for the Foundation Supernova Survey. We are using the Pan-STARRS telescope to obtain photometry for up to 800 SNe Ia at z<~0.1. This strategy has several unique advantages: (1) the Pan-STARRS system is a superbly calibrated telescopic system, (2) Pan-STARRS has observed 3/4 of the sky in grizyP1 making future template observations unnecessary, (3) we have a well-tested data-reduction pipeline, and (4) we have observed ~3000 high-redshift SNe Ia on this system. Here, we present our initial sample of 225 SN Ia grizP1 light curves, of which 180 pass all criteria for inclusion in a cosmological sample. The Foundation Supernova Survey already contains more cosmologically useful SNe Ia than all other published low-redshift SN Ia samples combined. We expect that the systematic uncertainties for the Foundation Supernova Sample will be two to three times smaller than other low-redshift samples. We find that our cosmologically useful sample has an intrinsic scatter of 0.111mag, smaller than other low-redshift samples. We perform detailed simulations showing that simply replacing the current low-redshift SN Ia sample with an equally sized Foundation sample will improve the precision on the dark energy equation-of-state parameter by 35 per cent, and the dark energy figure of merit by 72 per cent.
- ID:
- ivo://CDS.VizieR/J/other/Ap/52.40
- Title:
- FSS galaxies in southern hemisphere
- Short Name:
- J/other/Ap/52.40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the properties of the 3838 galaxies that were monitored for SNe events, including newly determined morphologies and their DENIS and POSS-II/UKST I, 2MASS and DENIS J and K_s_ and 2MASS H magnitudes. We have compared 2MASS, DENIS and POSS-II/UKST IJK magnitudes in order to find possible systematic photometric shifts in the measurements. The DENIS and POSS-II/UKST I band magnitudes show large discrepancies (mean absolute difference of 0.4mag), mostly due to different spectral responses of the two instruments, with an important contribution (0.33mag rms) from the large uncertainties in the photometric calibration of the POSS-II and UKST photographic plates. In the other wavebands, the limiting near infrared magnitude, morphology, and inclination of the galaxies are the most influential factors which affect the determination of photometry of the galaxies. Nevertheless, no significant systematic differences have been found between of any pair of NIR magnitude measurements, except for a few percent of galaxies showing large discrepancies. This allows us to combine DENIS and 2MASS data for the J and K_s_ filters.
- ID:
- ivo://CDS.VizieR/J/other/ApSS/365.89
- Title:
- Gaia Alerts with LAMOST and SDSS
- Short Name:
- J/other/ApSS/365
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ESA-Gaia satellite is regularly producing Alerts on objects where photometric variability has been detected after several passages over the same region of the sky. The physical nature of these objects has often to be determined with the help of complementary observations from ground-based facilities. We have compared the list of Gaia Alerts (from the beginning in 2014 to Nov. 1st, 2018) with archival LAMOST and SDSS spectroscopic data. A search radius of 3" has been adopted. In using survey data, the date of the ground-based observation rarely corresponds to the date of the Alert, but this allows at least the identification of the source if it is persistent, or the host galaxy if the object was only transient like a supernova (SN). Some of the objects have several LAMOST observations, and we complemented this search by adding also SDSS DR15 data in order to look for long-term variability. A list of Gaia Nuclear Transients (GNT) from Kostrzewa-Rutkowska et al. (2018. 2018MNRAS.481..307K, Cat. J/MNRAS/481/307), has been included in this search also. We found 26 Gaia Alerts with spectra in LAMOST+SDSS labelled as stars, among which 12 have multi-epoch spectra. A majority of them are Cataclysmic Variables (CVs). Similarly, 206 Gaia Alerts have associated spectra labelled as galaxies, among which 49 have multi-epoch spectra. Those spectra were generally obtained on a date widely different from the Alert date, and are mostly emission-line galaxies with no particularity (except a few Seyferts), leading to the suspicion that most of the Alerts were due to a SN. As for the GNT list, we found 55 associated spectra labelled as galaxies, among them 13 with multi-epoch spectra. In these two galaxy samples, in only two cases, Gaia17aal and GNTJ170213+2543, was the date of the spectroscopic observation close enough to the Alert date: we find a trace of the SN itself in their LAMOST spectrum, both being now classified here as a type Ia SN. Compared to the galaxy sample from the Gaia alerts, the GNT sample has a higher proportion of AGNs, suggesting that some of the detected variations are also due to the AGN itself. Similarly for Quasars, we found only 30 Gaia Alerts but 68 GNT cases associated with single epoch quasar spectra in the databases. In addition to those, 12 plus 23 are quasars where multi-epoch spectra are available. For ten out of these 35, their multi-epoch spectra show appearance or disappearance of the broad Balmer lines and also variations in the continuum, qualifying them as "Changing Look Quasars" and therefore significantly increasing the available sample of such objects.
- ID:
- ivo://CDS.VizieR/J/MNRAS/481/307
- Title:
- Gaia Nuclear Transient (GNT) cand.
- Short Name:
- J/MNRAS/481/307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The high spatial resolution and precise astrometry and photometry of the Gaia mission should make it particularly apt at discovering and resolving transients occurring in, or near, the centres of galaxies. Indeed, some nuclear transients are reported by the Gaia Science Alerts (GSA) team, but not a single confirmed tidal disruption event (TDE) has been published. In order to explore the sensitivity of GSA, we performed an independent and systematic search for nuclear transients using Gaia observations. Our transient search is driven from an input galaxy catalogue (derived from the Sloan Digital Sky Survey Release 12). We present a candidate detection metric that is independent from the existing GSA methodology, to see if Gaia Alerts are biased against the discovery of nuclear transients, and in particular which steps may have an impact. Our technique does require significant manual vetting of candidates, making implementation in the GSA system impractical for daily operations, although it could be run weekly, which for month-to-year long transients would make a scientifically valuable addition. Our search yielded 480 nuclear transients, 5 of which were alerted and published by GSA. The list of (in some cases ongoing) transients includes candidates for events related to enhanced accretion on to a super-massive black hole and TDEs. An implementation of the detection methodology and criteria used in this paper as an extension of GSA could open up the possibility for Gaia to fulfil the role as a main tool to find transient nuclear activity as predicted in the literature.
- 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.
- 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/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.
