Search

Start Over Subject galaxies Rights public
3261. SNe/SNRs in starburst galaxy Arp 220
ID:
ivo://CDS.VizieR/J/A+A/623/A173
Title:
SNe/SNRs in starburst galaxy Arp 220
Short Name:
J/A+A/623/A173
Date:
21 Oct 2021
Publisher:
CDS
Description:
The nearby ultra-luminous infrared galaxy (ULIRG) Arp 220 is an excellent laboratory for studies of extreme astrophysical environments. For 20 years, Very Long Baseline Interferometry (VLBI) has been used to monitor a population of compact sources thought to be supernovae (SNe), supernova remnants (SNRs) and possibly active galactic nuclei (AGNs). SNe and SNRs are thought to be the sites of relativistic particle acceleration powering the star formation induced radio emission, and are hence important for studies of e.g. the origin of the FIR-radio correlation. In this work we aim for a self-consistent analysis of a large collection of Arp 220 continuum VLBI data sets. With more data and improved consistency in calibration and imaging, we aim to detect more sources and improve source classifications with respect to previous studies. Furthermore, we aim to increase the number of sources with robust size estimates, to analyse the compact source luminosity function (LF), and to search for a luminosity-diameter (LD) relation within Arp 220. Using new and archival VLBI data spanning 20 years, we obtain 23 high-resolution radio images of Arp 220 at wavelengths from 18cm to 2cm. From model-fitting to the images we obtain estimates of flux densities and sizes of all detected sources. The sources are classified in groups according to their observed lightcurves, spectra and sizes. We fit a multi-frequency supernova lightcurve model to the object brightest at 6cm to estimate explosion properties for this object.
3262. SN host galaxies basic information
ID:
ivo://CDS.VizieR/J/ApJ/791/57
Title:
SN host galaxies basic information
Short Name:
J/ApJ/791/57
Date:
21 Oct 2021
Publisher:
CDS
Description:
We compare the host galaxies of 902 supernovae (SNe), including SNe Ia, SNe II, and SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog (Barbon et al., cat II/227) with the Sloan Digital Sky Survey (SDSS) Data Release 7 (Strauss et al., 2002AJ....124.1810S). We selected an additional 213 galaxies by requiring the light fraction of spectral observations to be >15%, which could represent well the global properties of the galaxies. Among these 213 galaxies, 135 appear on the Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in terms of whether they are star-forming (SF) galaxies, active galactic nuclei (AGNs; including composites, LINERs, and Seyfert 2s) or absorption-line galaxies (Absorps; i.e., their related emission lines are weak or non-existent). The diagrams related to the parameters D_n_(4000), H{delta}_A_, stellar masses, star formation rates (SFRs), and specific SFRs for the SNe hosts show that almost all SNe II and most of the SNe Ibc occur in SF galaxies, which have a wide range of stellar masses and low D_n_(4000). The SNe Ia hosts as SF galaxies following similar trends. A significant fraction of SNe Ia occurs in AGNs and absorption-line galaxies, which are massive and have high D_n_(4000). The stellar population analysis from spectral synthesis fitting shows that the hosts of SNe II have a younger stellar population than hosts of SNe Ia. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures less than 15% of the total light. These comparison galaxies appear biased toward higher 12+log(O/H) (~0.1 dex) at a given stellar mass. Therefore, we believe the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.
3263. SN.Ia host galaxies properties
ID:
ivo://CDS.VizieR/J/ApJ/740/92
Title:
SN.Ia host galaxies properties
Short Name:
J/ApJ/740/92
Date:
21 Oct 2021
Publisher:
CDS
Description:
We improve estimates of the stellar mass and mass-weighted average age of Type Ia supernova (SN Ia) host galaxies by combining UV and near-IR photometry with optical photometry in our analysis. Using 206 SNe Ia drawn from the full three-year Sloan Digital Sky Survey (SDSS-II) Supernova Survey and multi-wavelength host-galaxy photometry from SDSS, the Galaxy Evolution Explorer, and the United Kingdom Infrared Telescope Infrared Deep Sky Survey, we present evidence of a correlation (1.9{sigma} confidence level) between the residuals of SNe Ia about the best-fit Hubble relation and the mass-weighted average age of their host galaxies. The trend is such that older galaxies host SNe Ia that are brighter than average after standard light-curve corrections are made. We also confirm, at the 3.0{sigma} level, the trend seen by previous studies that more massive galaxies often host brighter SNe Ia after light-curve correction.
3264. SN Ia host galaxies SFR from SDSS-II
ID:
ivo://CDS.VizieR/J/ApJ/755/61
Title:
SN Ia host galaxies SFR from SDSS-II
Short Name:
J/ApJ/755/61
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using data from the Sloan Digital Sky Supernova Survey-II (SDSS-II SN Survey, Frieman et al., 2008AJ....135..338F), we measure the rate of Type Ia supernovae (SNe Ia) as a function of galaxy properties at intermediate redshift. A sample of 342 SNe Ia with 0.05<z<0.25 is constructed. Using broadband photometry and redshifts, we use the P\'EGASE.2 spectral energy distributions to estimate host galaxy stellar masses and recent star formation rates (SFRs).
3265. SN 2008iz 4.8 and 8.4GHz images
ID:
ivo://CDS.VizieR/J/A+A/593/A18
Title:
SN 2008iz 4.8 and 8.4GHz images
Short Name:
J/A+A/593/A18
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on multi-frequency Very Large Array (VLA) and Very Long Baseline Interferometry (VLBI) radio observations for a monitoring campaign of supernova SN 2008iz in the nearby irregular galaxy M82.
3266. SN 2014J BV light curves
ID:
ivo://CDS.VizieR/J/A+A/585/A19
Title:
SN 2014J BV light curves
Short Name:
J/A+A/585/A19
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results of high-cadence monitoring of the optical light curve of the nearby, Type Ia SN 2014J in M82, using the 2.3m Aristarchos telescope. B and V-band photometry on days 15-18 after tmax(B) was obtained with a cadence of 2 min per band, revealing evidence for rapid variability at the 0.02-0.05mag level on timescales of 15-60min on all four nights. The decline slope was measured as steeper in the B-band than in the V-band, and to steadily decrease in both bands from 0.15 mag/day (night 1) to 0.04mag/day (night 4) in V, and from 0.19mag/day (night 1) to 0.06mag/day (night 4) in B, corresponding to the onset of the secondary maximum. We propose that rapid variability could be due to one or a combination of the following scenarios: the clumpiness of the ejecta, their interaction with circumstellar material, the asymmetry of the explosion, or the mechanism causing the secondary maximum in the near-infrared light curve. We encourage the community to undertake high-cadence monitoring of future, nearby and bright supernovae to investigate the intraday behaviour of their light curves.
3267. SNRs in M33 from optical and X-ray
ID:
ivo://CDS.VizieR/J/ApJS/187/495
Title:
SNRs in M33 from optical and X-ray
Short Name:
J/ApJS/187/495
Date:
21 Oct 2021
Publisher:
CDS
Description:
M33 contains a large number of emission nebulae identified as supernova remnants (SNRs) based on the high [SII]:H{alpha} ratios characteristic of shocked gas. Using Chandra data from the ChASeM33 survey with a 0.35-2keV sensitivity of ~2x10^34^erg/s, we have detected 82 of 137 SNR candidates, yielding confirmation of (or at least strongly support for) their SNR identifications. A spectral analysis of the seven X-ray brightest SNRs reveals that two, G98-31 and G98-35, have spectra that appear to indicate enrichment by ejecta from core-collapse supernova explosions. We have used a combination of new and archival optical and radio observations to attempt to better understand why some objects are detected as X-ray sources and others are not. We have also developed a morphological classification scheme for the optically identified SNRs and discussed the efficacy of this scheme as a predictor of X-ray detectability. Finally, we have compared the SNRs found in M33 to those that have been observed in the Galaxy and the Magellanic Clouds.
3268. SNRs in six nearby galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/429/189
Title:
SNRs in six nearby galaxies
Short Name:
J/MNRAS/429/189
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a study of optically emitting supernova remnants (SNRs) in six nearby galaxies (NGC 2403, 3077, 4214, 4395, 4449 and 5204) based on deep narrow-band H{alpha} and [SII] images as well as spectroscopic observations. The SNR classification was based on the detected sources that fulfil the well-established emission-line flux criterion of [SII]/H{alpha}>0.4. This study revealed ~400 photometric SNRs down to a limiting H{alpha} flux of 10^-15^erg/s/cm^2^. Spectroscopic observations confirmed the shock-excited nature of 56 out of the 96 sources with ([SII]/H{alpha})_phot_>0.3 (our limit for an SNR classification) for which we obtained spectra. 11 more sources were spectroscopically identified as SNRs although their photometric [SII]/H{alpha} ratio was below 0.3. We discuss the properties of the optically detected SNRs in our sample for different types of galaxies and hence different environments, in order to address their connection with the surrounding interstellar medium. We find that there is a difference in [NII]/H{alpha} line ratios of the SNR populations between different types of galaxies which indicates that this happens due to metallicity. We cross-correlate parameters of the optically detected SNRs ([SII]/H{alpha} ratio, luminosity) with parameters of coincident X-ray-emitting SNRs, resulted from our previous studies on the same sample of galaxies, in order to understand their evolution and investigate possible selection effects. We do not find a correlation between their H{alpha} and X-ray luminosities, which we attribute to the presence of material in a wide range of temperatures. We also find evidence for a linear relation between the number of luminous optical SNRs (10^37^erg/s) and star formation rate in our sample of galaxies.
3269. S7 observations with WiFeS of active galaxies
ID:
ivo://CDS.VizieR/J/ApJS/217/12
Title:
S7 observations with WiFeS of active galaxies
Short Name:
J/ApJS/217/12
Date:
21 Oct 2021
Publisher:
CDS
Description:
Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph (WiFeS) mounted on the ANU 2.3m telescope located at the Siding Spring Observatory to deliver an integral field of 38x25 arcsec at a spectral resolution of R=7000 in the red (530-710nm), and R=3000 in the blue (340-560nm). From these data cubes we have extracted the narrow-line region spectra from a 4 arcsec aperture centered on the nucleus. We also determine the H{beta} and [OIII]{lambda}5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the H{beta} and [OIII]{lambda}5007 luminosities determined from spectra for which the stellar continuum has been removed. We present a set of images of the galaxies in [OIII]{lambda}5007, [NII]{lambda}6584, and H{alpha}, which serve to delineate the spatial extent of the extended narrow-line region and also to reveal the structure and morphology of the surrounding HII regions. Finally, we provide a preliminary discussion of those Seyfert 1 and Seyfert 2 galaxies that display coronal emission lines in order to explore the origin of these lines.
3270. Sodium excess objects. I. SDSS-DR7
ID:
ivo://CDS.VizieR/J/ApJS/208/7
Title:
Sodium excess objects. I. SDSS-DR7
Short Name:
J/ApJS/208/7
Date:
21 Oct 2021
Publisher:
CDS
Description:
Several studies have reported the presence of sodium excess objects having neutral atomic absorption lines at 5895{AA} (Na.D) and 8190{AA} that are deeper than expected based on stellar population models that match the stellar continuum. The origin of these lines is therefore hotly debated. van Dokkum & Conroy (2010Natur.468..940V) proposed that low-mass stars (<~0.3M_{sun}_) are more prevalent in massive early-type galaxies, which may lead to a strong Na I 8190 line strength. It is necessary to test this prediction, however, against other prominent optical line indices such as Na.D, Mg b, and Fe 5270, which can be measured with a significantly higher signal-to-noise ratio than Na I 8190. We identified a new sample of roughly 1000 Na.D excess objects (NEOs; ~8% of galaxies in the sample) based on Na.D line strength in the redshift range 0.00<=z<=0.08 from the Sloan Digital Sky Survey (SDSS) DR7 through detailed analysis of galaxy spectra. We explore the properties of these new objects here. The novelty of this work is that the galaxies were carefully identified through direct visual inspection of SDSS images, and we systematically compared the properties of NEOs and those of a control sample of galaxies with normal Na.D line strengths. We note that the majority of galaxies with high velocity dispersions ({sigma}_e_>250km/s) show Na.D excesses.