- ID:
- ivo://CDS.VizieR/J/ApJ/903/31
- Title:
- Photometry AT 2018hyz with Swift XRT, UVOT and Swope
- Short Name:
- J/ApJ/903/31
- Date:
- 11 Mar 2022 14:12:05
- Publisher:
- CDS
- Description:
- We present the multiwavelength analysis of the tidal disruption event (TDE) AT2018hyz (ASASSN-18zj). From follow-up optical spectroscopy, we detect the first unambiguous case of resolved double-peaked Balmer emission in a TDE. The distinct line profile can be well-modeled by a low eccentricity (e~0.1) accretion disk extending out to ~100Rp and a Gaussian component originating from non-disk clouds, though a bipolar outflow origin cannot be completely ruled out. Our analysis indicates that in AT2018hyz, disk formation took place promptly after the most-bound debris returned to pericenter, which we estimate to be roughly tens of days before the first detection. Redistribution of angular momentum and mass transport, possibly through shocks, must occur on the observed timescale of about a month to create the large H{alpha}-emitting disk that comprises <~5% of the initial stellar mass. With these new insights from AT2018hyz, we infer that circularization is efficient in at least some, if not all optically bright, X-ray faint TDEs. In these efficiently circularized TDEs, the detection of double-peaked emission depends on the disk inclination angle and the relative strength of the disk contribution to the non-disk component, possibly explaining the diversity seen in the current sample.
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- ID:
- ivo://CDS.VizieR/J/ApJ/736/159
- Title:
- Photometry monitoring of the SN PTF10vdl
- Short Name:
- J/ApJ/736/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Palomar Transient Factory (PTF) is an optical wide-field variability survey carried out using a camera with a 7.8deg^2^ field of view mounted on the 48 inch Oschin Schmidt telescope at Palomar Observatory. One of the key goals of this survey is to conduct high-cadence monitoring of the sky in order to detect optical transient sources shortly after they occur. Here, we describe the real-time capabilities of the PTF and our related rapid multiwavelength follow-up programs, extending from the radio to the {gamma}-ray bands. We present as a case study observations of the optical transient PTF10vdl (SN 2010id), revealed to be a very young core-collapse (Type II-P) supernova having a remarkably low luminosity. Our results demonstrate that the PTF now provides for optical transients the real-time discovery and rapid-response follow-up capabilities previously reserved only for high-energy transients like gamma-ray bursts.
- ID:
- ivo://CDS.VizieR/J/A+A/568/A19
- Title:
- Photometry of 3 {gamma}-ray burst supernovae
- Short Name:
- J/A+A/568/A19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared (NIR) photometry for three gamma-ray burst supernovae (GRB-SNe): GRB 120729A, GRB 130215A/SN 2013ez and GRB 130831A/SN 2013fu. For GRB 130215A/SN 2013ez, we also present optical spectroscopy at t-t0=16.1d, which covers rest-frame 3000-6250{AA}. Based on FeII (5169) and SiII (6355), our spectrum indicates an unusually low expansion velocity of 4000-6350km/s, the lowest ever measured for a GRB-SN. Additionally, we determined the brightness and shape of each accompanying SN relative to a template supernova (SN 1998bw), which were used to estimate the amount of nickel produced via nucleosynthesis during each explosion. We find that our derived nickel masses are typical of other GRB-SNe, and greater than those of SNe Ibc that are not associated with GRBs. For GRB 130831A/SN 2013fu, we used our well-sampled R-band light curve (LC) to estimate the amount of ejecta mass and the kinetic energy of the SN, finding that these too are similar to other GRB-SNe. For GRB 130215A, we took advantage of contemporaneous optical/NIR observations to construct an optical/NIR bolometric LC of the afterglow. We fit the bolometric LC with the millisecond magnetar model of Zhang & Meszaros (2001ApJ...552L..35Z), which considers dipole radiation as a source of energy injection to the forward shock powering the optical/NIR afterglow. Using this model we derive an initial spin period of P=1ms and a magnetic field of B=1.1x10^15^G, which are commensurate with those found for proposed magnetar central engines of other long-duration GRBs.
- ID:
- ivo://CDS.VizieR/J/ApJ/728/14
- Title:
- Photometry of SN 2009bb
- Short Name:
- J/ApJ/728/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ultraviolet, optical, and near-infrared photometry and optical spectroscopy of the broad-lined Type Ic supernova (SN) 2009bb are presented, following the flux evolution from -10 to +285 days past B-band maximum. Thanks to the very early discovery, it is possible to place tight constraints on the SN explosion epoch. The expansion velocities measured from near maximum spectra are found to be only slightly smaller than those measured from spectra of the prototype broad-lined SN 1998bw associated with GRB 980425. Fitting an analytical model to the pseudobolometric light curve of SN 2009bb suggests that 4.1+/-1.9M_{sun}_ of material was ejected with 0.22+/-0.06M_{sun} of it being ^56^Ni. The resulting kinetic energy is 1.8+/-0.7x10^52^erg. This, together with an absolute peak magnitude of M_B_=-18.36+/-0.44, places SN 2009bb on the energetic and luminous end of the broad-lined Type Ic (SN Ic) sequence. Detection of helium in the early time optical spectra accompanied with strong radio emission and high metallicity of its environment makes SN 2009bb a peculiar object. Similar to the case for gamma-ray bursts (GRBs), we find that the bulk explosion parameters of SN 2009bb cannot account for the copious energy coupled to relativistic ejecta, and conclude that another energy reservoir (a central engine) is required to power the radio emission. Nevertheless, the analysis of the SN 2009bb nebular spectrum suggests that the failed GRB detection is not imputable to a large angle between the line-of-sight and the GRB beamed radiation. Therefore, if a GRB was produced during the SN 2009bb explosion, it was below the threshold of the current generation of {gamma}-ray instruments.
- ID:
- ivo://CDS.VizieR/J/MNRAS/369/1880
- Title:
- Photometry of SN 2003cg
- Short Name:
- J/MNRAS/369/1880
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared photometry and spectroscopy of the Type Ia SN 2003cg, which exploded in the nearby galaxy NGC 3169. The observations cover a period between 8.5 and +414d post-maximum. SN 2003cg is a normal but highly reddened Type Ia event. Its B magnitude at maximum Bmax=15.94+/-0.04 and {Delta}m15(B)_obs_=1.12+/-0.04 [{Delta}m15(B)_intrinsic_=1.25+/-0.05]. Allowing RV to become a free parameter within the Cardelli et al. (1989ApJ...345..245C) extinction law, simultaneous matches to a range of colour curves of normal SNe Ia yielded E(B-V)=1.33+/-0.11, and RV=1.80+/-0.19. While the value obtained for RV is small, such values have been invoked in the past, and may imply a grain size which is small compared with the average value for the local interstellar medium.
- ID:
- ivo://CDS.VizieR/J/ApJ/692/L84
- Title:
- Photometry of SN 2008D
- Short Name:
- J/ApJ/692/L84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On 2008 January 9.56 UT, SN 2008D was discovered while following up an unusually bright X-ray transient (XT) in the nearby spiral galaxy NGC 2770. We present early optical spectra (obtained 1.75 days after the XT) which allowed the first identification of the object as a supernova (SN) at redshift z=0.007. These spectra were acquired during the initial declining phase of the light curve, likely produced in the stellar envelope cooling after shock breakout, and rarely observed. They exhibit a rather flat spectral energy distribution with broad undulations, and a strong, W-shaped feature with minima at 3980 and 4190{AA} (rest frame). We also present extensive spectroscopy and photometry of the SN during the subsequent photospheric phase. Unlike SNe associated with gamma-ray bursts, SN 2008D displayed prominent He features and is therefore of Type Ib.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A39
- Title:
- Photometry of SN 2015da
- Short Name:
- J/A+A/635/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we report the results of the first ~four years of spectroscopic and photometric monitoring of the Type IIn supernova SN 2015da (also known as PSN J13522411+3941286, or iPTF16tu). The supernova exploded in the nearby spiral galaxy NGC 5337 in a relatively highly extinguished environment. The transient showed prominent narrow Balmer lines in emission at all times and a slow rise to maximum in all bands. In addition, early observations performed by amateur astronomers give a very well-constrained explosion epoch. The observables are consistent with continuous interaction between the supernova ejecta and a dense and extended H-rich circumstellar medium. The presence of such an extended and dense medium is difficult to reconcile with standard stellar evolution models, since the metallicity at the position of SN 2015da seems to be slightly subsolar. Interaction is likely the mechanism powering the light curve, as confirmed by the analysis of the pseudo bolometric light curve, which gives a total radiated energy >~10^51^erg. Modeling the light curve in the context of a supernova shock breakout through a dense circumstellar medium allowed us to infer the mass of the prexisting gas to be ~=8M_{sun}_, with an extreme mass-loss rate for the progenitor star ~=0.6M_{sun}_/yr, suggesting that most of the circumstellar gas was produced during multiple eruptive events. Near- and mid-infrared observations reveal a fluxexcess in these domains, similar to those observed in SN 2010jl and other interacting transients, likely due to preexisting radiatively heated dust surrounding the supernova. By modeling the infrared excess, we infer a mass >~0.4x10^-3^M_{sun}_ for the dust.
- ID:
- ivo://CDS.VizieR/J/A+A/592/A40
- Title:
- Photometry of SN 2013gh and iPTF13dge
- Short Name:
- J/A+A/592/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Temporal variability of narrow absorption lines in high-resolution spectra of Type Ia supernovae (SNe Ia) is studied to search for circumstellar matter. Time series which resolve the profiles of absorption lines such as NaI D or CaII H&K are expected to reveal variations due to photoionisation and subsequent recombination of the gases. The presence, composition, and geometry of circumstellar matter may hint at the elusive progenitor system of SNe Ia and could also affect the observed reddening law. To date, there are few known cases of time-varying NaI D absorption in SNe Ia, all of which occurred during relatively late phases of the supernova (SN) evolution. Photoionisation, however, is predicted to occur during the early phases of SNe Ia, when the supernovae peak in the ultraviolet. We attempt, therefore, to observe early-time absorption-line variations by obtaining high-resolution spectra of SNe before maximum light We have obtained photometry and high-resolution spectroscopy of SNe Ia 2013gh and iPTF 13dge, to search for absorption- line variations. Furthermore, we study interstellar absorption features in relation to the observed photometric colours of the SNe. Results. Both SNe display deep NaI D and CaII H&K absorption features. Furthermore, small but significant variations are detected in a feature of the NaI D profile of SN 2013gh. The variations are consistent with either geometric effects of rapidly moving or patchy gas clouds or photoionisation of NaI gas at R~=10^19^cm from the explosion. Our analysis indicates that it is necessary to focus on early phases to detect photoionisation effects of gases in the circumstellar medium of SNe Ia. Different absorbers such as NaI and CaII can be used to probe for matter at different distances from the SNe. The nondetection of variations during early phases makes it possible to put limits on the abundance of the species at those distances.
- ID:
- ivo://CDS.VizieR/J/A+A/605/A6
- Title:
- Photometry of supernova iPTF13z
- Short Name:
- J/A+A/605/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical photometry of Type IIn SN iPTF13z, obtained by the intermediate Palomar Transient Factory (iPTF) collaboration using the 1.2m Samuel Oschin telescope and the 1.52m telescope at Palomar Observatory, California, USA.
- ID:
- ivo://CDS.VizieR/J/ApJ/760/L33
- Title:
- Photometry of the Ic supernova PTF12gzk
- Short Name:
- J/ApJ/760/L33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery and extensive early-time observations of the Type Ic supernova (SN) PTF12gzk. Our light curves show a rise of 0.8mag within 2.5hr. Power-law fits (f(t){prop.to}(t-t_0_)^n^) to these data constrain the explosion date to within one day. We cannot rule out a quadratic fireball model, but higher values of n are possible as well for larger areas in the fit parameter space. Our bolometric light curve and a dense spectral sequence are used to estimate the physical parameters of the exploding star and of the explosion. We show that the photometric evolution of PTF12gzk is slower than that of most SNe Ic. The high ejecta expansion velocities we measure (~30000km/s derived from line minima four days after explosion) are similar to the observed velocities of broad-lined SNe Ic associated with gamma-ray bursts (GRBs) rather than to normal SN Ic velocities. Yet, this SN does not show the persistent broad lines that are typical of broad-lined SNe Ic. The host-galaxy characteristics are also consistent with GRB-SN hosts, and not with normal SN Ic hosts. By comparison with the spectroscopically similar SN 2004aw, we suggest that the observed properties of PTF12gzk indicate an initial progenitor mass of 25-35M_{sun}_ and a large ((5-10)x10^51^erg) kinetic energy, the later being close to the regime of GRB-SN properties.
