- ID:
- ivo://CDS.VizieR/J/MNRAS/442/844
- Title:
- BVRI light curves of type II-P supernovae
- Short Name:
- J/MNRAS/442/844
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a sample of 23 Type II plateau supernovae (SNe II-P), all observed with the same set of instruments. Analysis of their photometric evolution confirms that their typical plateau duration is 100 d with little scatter, showing a tendency to get shorter for more energetic SNe. We examine the claimed correlation between the luminosity and the rise time from explosion to plateau. We analyse their spectra, measuring typical ejecta velocities, and confirm that they follow a well-behaved power-law decline. We find indications of high-velocity material in the spectra of six of our SNe. We test different dust-extinction correction methods by asking the following - does the uniformity of the sample increase after the application of a given method? A reasonably behaved underlying distribution should become tighter after correction. No method we tested made a significant improvement.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/487/832
- Title:
- BVRI photometry of the Type II-P SN 2017eaw
- Short Name:
- J/MNRAS/487/832
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Broadband BVRI light curves of SN 2017eaw in NGC 6946 reveal the classic elements of a Type II-P supernova. The observations were begun on 16 May 2017 (UT), approximately 1 d after the discovery was announced, and the photometric monitoring was carried out over a period of nearly 600d. The light curves show a well-defined plateau and an exponential tail which curves slightly at later times. An approximation to the bolometric light curve is derived and used to estimate the amount of ^56^Ni created in the explosion; from various approaches described in the literature, we obtain M(^56^Ni)=0.115_-0.022_^+0.027^M_{sun}_. We also estimate that 43 per cent of the bolometric flux emitted during the plateau phase is actually produced by the ^56^Ni chain. Other derived parameters support the idea that the progenitor was a red supergiant.
- ID:
- ivo://CDS.VizieR/J/ApJ/875/136
- Title:
- BVRI, spectra & IR obs. of type II-P SN2017eaw
- Short Name:
- J/ApJ/875/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive optical photometric and spectroscopic observations, from 4 to 482 days after explosion, of the Type II-plateau (II-P) supernova (SN) 2017eaw in NGC 6946. SN 2017eaw is a normal SN II-P intermediate in properties between, for example, SN 1999em and SN 2012aw and the more luminous SN 2004et, also in NGC6946. We have determined that the extinction to SN 2017eaw is primarily due to the Galactic foreground and that the SN site metallicity is likely subsolar. We have also independently confirmed a tip-of-the-red-giant-branch (TRGB) distance to NGC 6946 of 7.73+/-0.78Mpc. The distances to the SN that we have also estimated via both the standardized candle method and expanding photosphere method corroborate the TRGB distance. We confirm the SN progenitor identity in pre-explosion archival Hubble Space Telescope (HST) and Spitzer Space Telescope images, via imaging of the SN through our HST Target of Opportunity program. Detailed modeling of the progenitor's spectral energy distribution indicates that the star was a dusty, luminous red supergiant consistent with an initial mass of ~15M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/AJ/139/519
- Title:
- Carnegie supernova project. SNe Ia
- Short Name:
- J/AJ/139/519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Carnegie Supernova Project (CSP) is a five-year survey being carried out at the Las Campanas Observatory to obtain high-quality light curves of ~100 low-redshift Type Ia supernovae (SNe Ia) in a well-defined photometric system. Here we present the first release of photometric data that contains the optical light curves of 35 SNe Ia, and near-infrared light curves for a subset of 25 events. The data comprise 5559 optical (ugriBV) and 1043 near-infrared (Y JHKs) data points in the natural system of the Swope telescope. Twenty-eight SNe have pre-maximum data, and for 15 of these, the observations begin at least 5 days before B maximum. This is one of the most accurate data sets of low-redshift SNe Ia published to date. When completed, the CSP data set will constitute a fundamental reference for precise determinations of cosmological parameters, and serve as a rich resource for comparison with models of SNe Ia.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A150
- Title:
- CasA, CygA, TauA, VirA 30MHz & 77MHz models
- Short Name:
- J/A+A/635/A150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The four persistent radio sources in the northern sky with the highest flux density at metre wavelengths are Cassiopeia A, Cygnus A, Taurus A, and Virgo A; collectively they are called the A-team. Their flux densities at ultra-low frequencies (<100MHz) can reach several thousands of janskys, and they often contaminate observations of the low-frequency sky by interfering with image processing. Furthermore, these sources are foreground objects for all-sky observations hampering the study of faint signals, such as the cosmological 21cm line from the epoch of reionisation. We aim to produce robust models for the surface brightness emission as a function of frequency for the A-team sources at ultra-low frequencies. These models are needed for the calibration and imaging of wide-area surveys of the sky with low-frequency interferometers. This requires obtaining images at an angular resolution better than 1500 with a high dynamic range and good image fidelity. We observed the A-team with the Low Frequency Array (LOFAR) at frequencies between 30MHz and 77MHz using the Low Band Antenna (LBA) system. We reduced the datasets and obtained an image for each A-team source. The paper presents the best models to date for the sources Cassiopeia A, Cygnus A, Taurus A, and Virgo A between 30MHz and 77MHz. We were able to obtain the aimed resolution and dynamic range in all cases. Owing to its compactness and complexity, observations with the long baselines of the International LOFAR Telescope will be required to improve the source model for Cygnus A further.
- ID:
- ivo://CDS.VizieR/J/ApJ/696/870
- Title:
- Catalina Real-time Transient Survey (CRTS)
- Short Name:
- J/ApJ/696/870
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the results from the first six months of the Catalina Real-Time Transient Survey (CRTS). In order to search for optical transients (OTs) with timescales of minutes to years, the CRTS analyses data from the Catalina Sky Survey which repeatedly covers 26000 of square degrees on the sky. The CRTS provides a public stream of transients that are bright enough to be followed up using small telescopes. Since the beginning of the survey, all CRTS transients have been made available to astronomers around the world in real time using HTML tables, RSS feeds, and VOEvents. As part of our public outreach program, the detections are now also available in Keyhole Markup Language through Google Sky. The initial discoveries include over 350 unique OTs rising more than 2mag from past measurements. Sixty two of these are classified as supernovae (SNe), based on light curves, prior deep imaging and spectroscopic data. Seventy seven are due to cataclysmic variables (CVs; only 13 previously known), while an additional 100 transients were too infrequently sampled to distinguish between faint CVs and SNe. The remaining OTs include active galactic nucleus, blazars, high-proper-motions stars, highly variable stars (such as UV Ceti stars), and transients of an unknown nature.
- ID:
- ivo://CDS.VizieR/J/ApJS/213/9
- Title:
- Catalina Surveys periodic variable stars
- Short Name:
- J/ApJS/213/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ~47000 periodic variables found during the analysis of 5.4 million variable star candidates within a 20000deg^2^ region covered by the Catalina Surveys Data Release-1 (CSDR1). Combining these variables with type ab RR Lyrae from our previous work, we produce an online catalog containing periods, amplitudes, and classifications for ~61000 periodic variables. By cross-matching these variables with those from prior surveys, we find that >90% of the ~8000 known periodic variables in the survey region are recovered. For these sources, we find excellent agreement between our catalog and prior values of luminosity, period, and amplitude as well as classification. We investigate the rate of confusion between objects classified as contact binaries and type c RR Lyrae (RRc's) based on periods, colors, amplitudes, metallicities, radial velocities, and surface gravities. We find that no more than a few percent of the variables in these classes are misidentified. By deriving distances for this clean sample of ~5500 RRc's, we trace the path of the Sagittarius tidal streams within the Galactic halo. Selecting 146 outer-halo RRc's with SDSS radial velocities, we confirm the presence of a coherent halo structure that is inconsistent with current N-body simulations of the Sagittarius tidal stream. We also find numerous long-period variables that are very likely associated within the Sagittarius tidal stream system. Based on the examination of 31000 contact binary light curves we find evidence for two subgroups exhibiting irregular light curves. One subgroup presents significant variations in mean brightness that are likely due to chromospheric activity. The other subgroup shows stable modulations over more than a thousand days and thereby provides evidence that the O'Connell effect is not due to stellar spots.
- ID:
- ivo://CDS.VizieR/J/ApJS/92/219
- Title:
- Catalog of recent supernovae
- Short Name:
- J/ApJS/92/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A listing is given of all supernovae discovered between 1989 January 1 and 1993 April 1. The data show no evidence for a significant dependence of the discovery probability of supernovae on parent galaxy inclination to the line of sight. If no inclination corrections need to be applied, then the supernova rates in spirals are only about half as large as previously believed. The mean linear separation of supernovae of type II (SNe II) from the center of their parent galaxy increases with increasing distance (Shaw effect). The Shaw effect appears less evident, or absent, for (more luminous) supernovae of type Ia. The data are consistent with, but do not prove, the hypothesis that (presumably reddened) SNe II are more likely to be discovered in the red than in the blue. Due to intensive surveillance, most bright SNe Ia tend to be found before maximum, whereas the majority of faint SNe Ia are discovered after maximum light.
- ID:
- ivo://CDS.VizieR/J/ApJ/522/802
- Title:
- Cepheid calibration of SN 1989B in NGC 3627
- Short Name:
- J/ApJ/522/802
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Repeated imaging observations have been made of NGC 3627 with the Hubble Space Telescope in 1997 - 1998 over an interval of 58 days. Images were obtained on 12 epochs in the F555W band and on five epochs in the F814W band. The galaxy hosted the prototypical, "Branch normal," type Ia supernova SN 1989B. A total of 83 variables have been found, of which 68 are definite Cepheid variables with periods ranging from 75 to 3.85 days. The dereddened distance modulus is determined to be (m-M)_o_=30.22{+/-}0.12 (internal uncertainty) using a subset of the Cepheid data whose reddening and error parameters are secure.
- ID:
- ivo://CDS.VizieR/J/ApJ/699/539
- Title:
- Cepheids in SN-Ia host galaxies
- Short Name:
- J/ApJ/699/539
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second of two papers reporting results from a program to determine the Hubble constant to ~5% precision from a refurbished distance ladder based on extensive use of differential measurements. Here we report observations of 240 Cepheid variables obtained with the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) Camera 2 through the F160W filter on the Hubble Space Telescope (HST). The Cepheids are distributed across six recent hosts of Type Ia supernovae (SNe Ia) and the "maser galaxy" NGC 4258, allowing us to directly calibrate the peak luminosities of the SNe Ia from the precise, geometric distance measurements provided by the masers. New features of our measurement include the use of the same instrument for all Cepheid measurements across the distance ladder and homogeneity of the Cepheid periods and metallicities, thus necessitating only a differential measurement of Cepheid fluxes and reducing the largest systematic uncertainties in the determination of the fiducial SN Ia luminosity. In addition, the NICMOS measurements reduce the effects of differential extinction in the host galaxies by a factor of ~5 over past optical data. Combined with a greatly expanded set of 240 SNe Ia at z<0.1 which define their magnitude-redshift relation, we find H_0_=74.2+/-3.6km/s/Mpc, a 4.8% uncertainty including both statistical and systematic errors.
