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3322. 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.
- 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.
- 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.
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/368/797
- Title:
- Soft X-ray properties of Seyfert galaxies
- Short Name:
- J/A+A/368/797
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of ROSAT detected sources in the sample of spectroscopically selected Seyfert 1 and Seyfert 2 galaxies of Rafanelli et al. (1995AJ....109.1546R). The catalogue contains 102 Seyfert 1 and 36 Seyfert 2 galaxies. The identification is based on X-ray contour maps overlaid on optical images taken from the Digitized Sky Survey. We have derived the basic spectral and timing properties of the X-ray detected Seyfert galaxies. For Seyfert 1 galaxies a strong correlation between photon index and X-ray luminosity is detected. We confirm the presence of generally steeper X-ray continua in narrow-line Seyfert 1 galaxies (NLS1s) compared to broad-line Seyfert 1 galaxies. Seyfert 2 galaxies show photon indices similar to those of NLS1s. Whereas a tendency for an increasing X-ray luminosity with increasing interaction strength is found for Seyfert 1 galaxies, such a correlation is not found for Seyfert 2 galaxies. For Seyfert 1 galaxies we found also a strong correlation for increasing far-infrared luminosity with increasing interaction strength. Both NLS1s and Seyfert 2 galaxies show the highest values of far-infrared luminosity compared to Seyfert 1 galaxies, suggesting that NLS1s and Seyfert 2 galaxies host strong (circumnuclear) star formation. For variable Seyfert galaxies we present the X-ray light curves obtained from the ROSAT All-Sky Survey and from ROSAT PSPC and HRI pointed observations. Besides the expected strong short- and long-term X-ray variability in Seyfert 1 galaxies, we find indications for X-ray flux variations in Seyfert 2 galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/897/5
- Title:
- 90 sources radio flux density from GLEAM and HERA
- Short Name:
- J/ApJ/897/5
- Date:
- 16 Mar 2022 00:49:20
- Publisher:
- CDS
- Description:
- The central challenge in 21cm cosmology is isolating the cosmological signal from bright foregrounds. Many separation techniques rely on the accurate knowledge of the sky and the instrumental response, including the antenna primary beam. For drift-scan telescopes, such as the Hydrogen Epoch of Reionization Array (HERA), that do not move, primary beam characterization is particularly challenging because standard beam-calibration routines do not apply (Cornwell et al.) and current techniques require accurate source catalogs at the telescope resolution. We present an extension of the method from Pober et al. where they use beam symmetries to create a network of overlapping source tracks that break the degeneracy between source flux density and beam response and allow their simultaneous estimation. We fit the beam response of our instrument using early HERA observations and find that our results agree well with electromagnetic simulations down to a -20dB level in power relative to peak gain for sources with high signal-to-noise ratio. In addition, we construct a source catalog with 90 sources down to a flux density of 1.4Jy at 151MHz.
- ID:
- ivo://CDS.VizieR/J/A+AS/110/371
- Title:
- Southern binary galaxies. I.
- Short Name:
- J/A+AS/110/371
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/125/329
- Title:
- Southern binary galaxies radial velocities
- Short Name:
- J/A+AS/125/329
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectrophotometry of a sample of 26 Southern binary galaxies. 17 pairs were confirmed to be physically associated with typical separation of 136h^-1^kpc. Pairs with velocity difference {DELTA}V>=600km/s are probably not physically bound. A comparison with field galaxies suggests that galaxies in pairs tend to have a younger population probably stimulated by tidal interaction. No correlation between the young population and projected separation was found. This table contains the quantities derived from the spectral data.
