M. M. Kasliwal

Hebrew University of Jerusalem, Yerushalayim, Jerusalem, Israel

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Publications (377)1461.21 Total impact

  • No preview · Article · Feb 2016 · The Astrophysical Journal

  • No preview · Article · Jan 2016 · Astronomy and Astrophysics
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    ABSTRACT: We present a systematic study of mid-infrared (mid-IR) emission from 141 nearby supernovae (SNe) observed with the InfraRed Array Camera (IRAC) on the Spitzer Space Telescope. These SNe reside in one of the 190 galaxies within 20Mpc drawn from the ongoing three-year SPIRITS program. Both new SPIRITS observations and data from other programs available in the archive are used in this study. We detect 8 Type Ia SNe and 36 core-collapse SNe. All Type I SNe fade and become undetectable within 3 years of explosion. About 22±11% of Type II SNe continue to be detected at late-times with five events detected even two decades after discovery. Dust luminosity, temperature, and mass are obtained by fitting the spectral energy distributions using photometry with IRAC bands 1 and 2. The dust mass estimate is a lower limit as the dust cloud could be optically thick or there could be cooler dust hiding at longer wavelengths. The estimate also does not distinguish between pre-existing and newly produced dust. We observe warm dust masses between 10^(-2) and 10^(-6) M_☉ and dust temperatures from 200K to 1280 K. We present detailed case studies of two extreme Type II-P SNe: SN2011ja and SN 2014bi. SN 2011ja was over-luminous ([4.5] = -15.6 mag) at 900 days post-explosion accompanied by a monotonic growth of the dust mass. This suggests either an episode of dust formation similar to SN 2004et and SN 2004dj, or an intensifying CSM interactions heating up pre-existing dust. SN 2014bi showed a factor of 10 decrease in dust mass over one month suggesting either an episode of dust destruction or a fading source of dust heating. A re-brightening in the mid-IR light curve of the Type Ib SN 2014C coinciding with a rise in the dust mass indicates either an episode of dust production perhaps via CSM interactions or more pre-existing dust getting heated up by the CSM interactions. This observation adds to a small number of stripped-envelope SNe that have mid-IR excess as has been previously reported in the case of SN 2006jc. The observed dust mass and the location of the CSM interactions suggest that the CSM shell around SN 2014C is originated from an LBV-like eruption roughly 100 years before the explosion. We also report detections of SN 1974E, SN 1979C, SN1980K, SN 1986J, and SN 1993J more than 20 years post-explosion. The number of outlying SNe identified in this work demonstrates the power of late time mid-IR observations of a large sample of SNe to identify events with unusual evolution.
    No preview · Article · Jan 2016
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    ABSTRACT: We have commenced a multi-year program, the Caltech-NRAO Stripe 82 Survey (CNSS), to search for radio transients with the Jansky VLA in the SDSS Stripe 82 region. The CNSS will deliver five epochs over the entire $\sim$270 deg$^2$ of Stripe 82, an eventual deep combined map with a rms noise of $\sim$40 $\mu$Jy and catalogs at a frequency of 3 GHz, and having a spatial resolution of 3". This first paper presents the results from an initial pilot survey of a 50 deg$^2$ region of Stripe 82, involving four epochs spanning logarithmic timescales between one week and 1.5 years, with the combined map having a median rms noise of 35 $\mu$Jy. This pilot survey enabled the development of the hardware and software for rapid data processing, as well as transient detection and follow-up, necessary for the full 270 deg$^2$ survey. Classification of variable and transient sources relied heavily on the wealth of multi-wavelength data in the Stripe 82 region, supplemented by repeated mapping of the region by the Palomar Transient Factory. $3.9^{+0.5}_{-0.9}$% of the detected point sources were found to vary by greater than 30%, consistent with similar studies at 1.4 GHz and 5 GHz. Multi-wavelength photometric data and light curves suggest that the variability is mostly due to shock-induced flaring in the jets of AGN. Although this was only a pilot survey, we detected two bona fide transients, associated with an RS CVn binary and a dKe star. Comparison with existing radio survey data revealed additional highly variable and transient sources on timescales between 5-20 years, largely associated with renewed AGN activity. The rates of such AGN possibly imply episodes of enhanced accretion and jet activity occurring once every $\sim$40,000 years in these galaxies. We compile the revised radio transient rates and make recommendations for future transient surveys and joint radio-optical experiments. (Abridged)
    No preview · Article · Jan 2016
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    ABSTRACT: While recent observations provide evidence that super-Chandrasekhar Type Ia supernovae and at least a fraction of normal Type Ia supernovae probably originate from double-degenerate systems, these two subclasses show distinct characteristics observationally. Here we report an intermediate supernova iPTF13asv that may bridge this gap. On the one hand, similar to normal Type Ia supernovae, the over-luminous iPTF13asv follows the empirical relation between the peak magnitude, the lightcurve shape and its intrinsic color, and shows a near-IR secondary maximum like normal supernovae. On the other hand, similar to super-Chandrasekhar events, it has strong UV emission around maximum, low expansion velocities and persistent carbon absorption. We estimate a ^(56)Ni mass of 0.81^(+0.10)_(-0.18) M_☉ and a total ejecta mass of 1.44^(+0.44)_(-0.12) M_☉. Despite these similarities, iPTF13asv lacks iron absorption in its early-phase spectra, indicating a stratified ejecta structure with weak mixing. Based on the strong stratification of the ejecta and the similarity to super-Chandrasekhar events, we infer that iPTF13asv probably originates from a double-degenerate system.
    Preview · Article · Jan 2016
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    ABSTRACT: Long duration y-ray bursts are thought to be a rare subclass of stripped-envelope core-collapse supernovae that launch collimated relativistic out ows (jets). All y-ray-burst-associated supernovae are spectroscopically of Type Ic with broad lines, but the fraction of broad-lined Type Ic supernovae harboring low-luminosity y-ray-bursts remains largely unconstrained. Some supernovae should be accompanied by off-axis y-ray burst jets that remain invisible initially, but then emerge as strong radio sources (as the jets decelerate). However, this critical prediction of the jet model for y-ray bursts has yet to be verified observationally. Here, we present K. G. Jansky Very Large Array radio observations of 15 broad-lined supernovae of Type Ic discovered by the Palomar Transient Factory in an untargeted manner. Most of the supernovae in our sample exclude radio emission observationally similar to that of the radio-loud, relativistic SN 1998bw. We thus constrain the fraction of 1998bw-like broad-lined Type Ic supernovae to be ≾ 14%. Most of the events in our sample also exclude off-axis jets similar to GRB031203 and GRB030329, but we cannot rule out off-axis y-ray-bursts expanding in a low-density wind environment. Three supernovae show late-time radio emission compatible with average speeds ≳ 0.3 c, on the dividing line between relativistic and "ordinary" supernovae. Based on these detections, we estimate that ≾ 45% of the broad-lined Type Ic supernovae in our sample may harbor off-axis y-ray-bursts expanding in media with densities in the range probed by this study.
    No preview · Article · Dec 2015
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    ABSTRACT: Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra ($\leq 10$ days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 Type II SNe showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14\% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18\% of SNe~II observed at ages $<5$ days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum which is similar to that of a black body, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude $M_R=-18.2$ belong to the FI or BF groups, and that all FI events peaked above $M_R=-17.6$ mag, significantly brighter than average SNe~II.
    No preview · Article · Dec 2015
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    ABSTRACT: During the first few days after explosion, Type II supernovae (SNe) are dominated by relatively simple physics. Theoretical predictions regarding early-time SN light curves in the ultraviolet (UV) and optical bands are thus quite robust. We present, for the first time, a sample of $57$ $R$-band Type II SN light curves that are well monitored during their rise, having $>5$ detections during the first 10 days after discovery, and a well-constrained time of explosion to within $1-3$ days. We show that the energy per unit mass ($E/M$) can be deduced to roughly a factor of five by comparing early-time optical data to the model of Rabinak & Waxman (2011), while the progenitor radius cannot be determined based on $R$-band data alone. We find that Type II SN explosion energies span a range of $E/M=(0.2-20)\times 10^{51} \; \rm{erg/(10 M}_\odot$), and have a mean energy per unit mass of $\left\langle E/M \right\rangle = 0.85\times 10^{51} \; \rm{erg/(10 M}_\odot$), corrected for Malmquist bias. Assuming a small spread in progenitor masses, this indicates a large intrinsic diversity in explosion energy. Moreover, $E/M$ is positively correlated with the amount of $^{56}\rm{Ni}$ produced in the explosion, as predicted by some recent models of core-collapse SNe. We further present several empirical correlations. The peak magnitude is correlated with the decline rate ($\Delta m_{15}$), the decline rate is weakly correlated with the rise time, and the rise time is not significantly correlated with the peak magnitude. Faster declining SNe are more luminous and have longer rise times. This limits the possible power sources for such events.
    Preview · Article · Nov 2015
  • R. Amanullah · Y. Cao · M. M. Phillips · M. M. Kasliwal
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    ABSTRACT: We present ultraviolet (UV) observations of six nearby Type Ia supernovae (SNe Ia) obtained with the Hubble Space Telescope, three of which were also observed in the near-IR (NIR) with Wide-Field Camera 3. UV observations with the Swift satellite, as well as ground-based optical and NIR data provide complementary information. The combined data set covers the wavelength range 0.2–2 μm. By also including archival data of SN 2014J, we analyse a sample spanning observed colour excesses up to E(B − V) = 1.4 mag. We study the wavelength-dependent extinction of each individual SN and find a diversity of reddening laws when characterized by the total-to-selective extinction R_V. In particular, we note that for the two SNe with E(B − V) ≳ 1 mag, for which the colour excess is dominated by dust extinction, we find R_V = 1.4 ± 0.1 and RV = 2.8 ± 0.1. Adding UV photometry reduces the uncertainty of fitted R_V by ∼50 per cent allowing us to also measure R_V of individual low-extinction objects which point to a similar diversity, currently not accounted for in the analyses when SNe Ia are used for studying the expansion history of the Universe.
    No preview · Article · Nov 2015
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    ABSTRACT: Supernovae Type Iax (SNe Iax) are less energetic and less luminous than typical thermonuclear explosions. A suggested explanation for the observed characteristics of this subclass is a binary progenitor system consisting of a CO white dwarf primary accreting from a helium star companion. A single-degenerate explosion channel might be expected to result in a dense circumstellar medium (CSM), although no evidence for such a CSM has yet been observed for this subclass. Here we present recent Spitzer observations of the SN Iax 2014dt obtained by the SPIRITS program nearly one year post-explosion that reveal a strong mid-IR excess over the expected fluxes of more normal SNe Ia. This excess is consistent with 1E-5 M_solar of newly formed dust, which would be the first time that newly formed dust has been observed to form in a normal Type Ia. The excess, however, is also consistent with a dusty CSM that was likely formed in pre-explosion mass-loss, thereby suggesting a single degenerate progenitor system. Compared to other SNe Ia that show significant shock interaction (SNe Ia-CSM) and interacting core-collapse events (SNe IIn), this dust shell in SN 2014dt is less massive. We consider the implications that such a pre-existing dust shell has for the progenitor system, including a binary system with a mass donor that is a red giant, a red supergiant, and an asymptotic giant branch star.
    Full-text · Article · Oct 2015
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    ABSTRACT: The IceCube neutrino observatory pursues a follow-up program selecting interesting neutrino events in real-time and issuing alerts for electromagnetic follow-up observations. In 2012 March, the most significant neutrino alert during the first three years of operation was issued by IceCube. In the follow-up observations performed by the Palomar Transient Factory (PTF), a Type IIn supernova (SN IIn) PTF12csy was found 0fdg2 away from the neutrino alert direction, with an error radius of 0.º54. It has a redshift of z = 0.0684, corresponding to a luminosity distance of about 300 Mpc and the Pan-STARRS1 survey shows that its explosion time was at least 158 days (in host galaxy rest frame) before the neutrino alert, so that a causal connection is unlikely. The a posteriori significance of the chance detection of both the neutrinos and the SN at any epoch is 2.2σ within IceCube's 2011/12 data acquisition season. Also, a complementary neutrino analysis reveals no long-term signal over the course of one year. Therefore, we consider the SN detection coincidental and the neutrinos uncorrelated to the SN. However, the SN is unusual and interesting by itself: it is luminous and energetic, bearing strong resemblance to the SN IIn 2010jl, and shows signs of interaction of the SN ejecta with a dense circumstellar medium. High-energy neutrino emission is expected in models of diffusive shock acceleration, but at a low, non-detectable level for this specific SN. In this paper, we describe the SN PTF12csy and present both the neutrino and electromagnetic data, as well as their analysis.
    No preview · Article · Sep 2015
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    ABSTRACT: The progenitor stars of several Type IIb supernovae (SNe) show indications for extended hydrogen envelopes. These envelopes might be the outcome of luminous energetic pre-explosion events, so-called precursor eruptions. We use the Palomar Transient Factory (PTF) pre-explosion observations of a sample of 27 nearby Type IIb SNe to look for such precursors during the final years prior to the SN explosion. No precursors are found when combining the observations in 15-day bins, and we calculate the absolute-magnitude-dependent upper limit on the precursor rate. At the 90% confidence level, Type IIb SNe have on average $<0.86$ precursors as bright as absolute $R$-band magnitude $-14$ in the final 3.5 years before the explosion and $<0.56$ events over the final year. In contrast, precursors among SNe IIn have a $\gtrsim 5$ times higher rate. The kinetic energy required to unbind a low-mass stellar envelope is comparable to the radiated energy of a few-weeks-long precursor which would be detectable for the closest SNe in our sample. Therefore, mass ejections, if they are common in such SNe, are radiatively inefficient or have durations longer than months. Indeed, when using 60-day bins a faint precursor candidate is detected prior to SN 2012cs ($\sim2$% false-alarm probability). We also report the detection of the progenitor of SN 2011dh which does not show detectable variability over the final two years before the explosion. The suggested progenitor of SN 2012P is still present, and hence is likely a compact star cluster, or an unrelated object.
    Preview · Article · Aug 2015 · The Astrophysical Journal
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    ABSTRACT: As part of the SDSS-IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will perform measurements of the cosmological distance scale via application of the Baryon Acoustic Oscillation (BAO) method to samples of quasars and galaxies. Quasar surveys are particularly useful in the BAO context as they can trace extremely large volumes back to moderately high redshift. eBOSS will adopt two approaches to target quasars over a 7500 sq. deg. area. First, z > 2.1 quasars will be targeted to improve BAO measurements in the Lyman-Alpha Forest. Second, a homogeneously selected "CORE" sample of quasars at 0.9 < z < 2.2 will be targeted to yield the first few-%-level BAO constraint near z~1.5. eBOSS CORE quasar targeting will combine optical selection in ugriz using a likelihood-based routine called XDQSOz, with a mid-IR-optical color-cut. A spectroscopic survey of ~300 sq. deg. of eBOSS targets shows that eBOSS CORE selection (to g < 22 OR r < 22) should return ~70 per sq. deg. 0.9 < z < 2.2 quasars and ~7 per sq. deg. z > 2.1 quasars. A supplemental selection based on variability of quasars in multi-epoch imaging from the Palomar Transient Factory should recover an additional ~3-4 per sq. deg. z > 2.1 quasars to g < 22.5. Regression tests demonstrate that a linear model of the effects of imaging systematics on target density can recover the angular distribution of CORE quasars over 96.7% (76.7%) of the SDSS North (South) Galactic Cap area. eBOSS is completely robust to changes in quasar target density due to imprecision in imaging zero points. Beyond its key cosmological goals, eBOSS should be the next-generation quasar survey, ultimately comprising > 500,000 new spectroscopically confirmed quasars and > 500,000 uniformly selected spectroscopically confirmed 0.9 < z < 2.2 quasars. At the conclusion of SDSS-IV, the SDSS will have provided unique spectra of over 800,000 quasars.
    Preview · Article · Aug 2015 · The Astrophysical Journal Supplement Series
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    ABSTRACT: In this work we continue a line of inquiry begun in Kanner et al. which detailed a strategy for utilizing telescopes with narrow fields of view, such as the Swift X-ray Telescope (XRT), to localize gravity wave (GW) triggers from LIGO/Virgo. If one considers the brightest galaxies that produce ~50% of the light, then the number of galaxies inside typical GW error boxes will be several tens. We have found that this result applies both in the early years of Advanced LIGO when the range is small and the error boxes large, and in the later years when the error boxes will be small and the range large. This strategy has the beneficial property of reducing the number of telescope pointings by a factor 10 to 100 compared with tiling the entire error box. Additional galaxy count reduction will come from a GW rapid distance estimate which will restrict the radial slice in search volume. Combining the bright galaxy strategy with a convolution based on anticipated GW localizations, we find that the searches can be restricted to about 18+/-5 galaxies for 2015, about 23+/-4 for 2017, and about 11+/-2 for 2020. This assumes a distance localization at or near the putative NS-NS merger range for each target year, and these totals are integrated out to the range. Integrating out to the horizon would roughly double the totals. For nearer localizations the totals would decrease. The galaxy strategy we present in this work will enable numerous sensitive optical and X-ray telescopes with small fields of view to participate meaningfully in searches wherein the prospects for rapidly fading afterglow place a premium on a fast response time.
    No preview · Article · Aug 2015
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    ABSTRACT: We present optical and near-infrared light curves and optical spectra of SN 2013dx, associated with the nearby (redshift 0.145) gamma-ray burst GRB130702A. The prompt isotropic gamma-ray energy released from GRB130702A is measured to be E ;iso = 6:4+1:3
    Full-text · Article · Aug 2015
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    ABSTRACT: We present extensive multiwavelength (radio to X-ray) observations of the Type Ib/c SN2013ge from −13 to +457 days relative to maximum light, including a series of optical spectra and Swift UV-optical photometry beginning 2 − 4 days post explosion. This makes SN2013ge one of the best observed normal Type Ib/c SN at early times, when the light curve is particularly sensitive to the progenitor configuration and mixing of radioactive elements. These early observations reveal two distinct light curve components in the UV bands. The first component rises over 4 − 5 days and is visible for the first week post-explosion. Spectra of the first component have a blue continuum and show a plethora of high velocity (~ 14,000 km s^(−1)) but narrow (~ 3500 km s^(−1)) spectroscopic features, indicating that the line forming region is restricted. The explosion parameters estimated for the bulk explosion (M_(ej) ~ 2 − 3 M_⊙; EK ~ 1 − 2 × 10^(51) ergs) are standard for Type Ib/c SN, while detailed analysis of optical and NIR spectra identify weak He features at early times (in an object which would have otherwise been classified as Type Ic), and nebular spectra show evidence for mixing and asymmetry in the bulk ejecta. In addition, SN2013ge exploded in a low metallicity environment (~ 0.5 Z_⊙) and we have obtained some of the deepest radio and X-ray limits for a Type Ib/c SN to date that constrain the progenitor mass-loss rate to be M < 4 × 10^(−6) M_⊙ yr^(−1). We are left with two distinct progenitor scenarios for SN2013ge depending on our interpretation of the early emission. If the first component is cooling envelope emission, then the progenitor of SN2013ge possessed a low-mass extended (≳ 30 R_⊙) envelope. Alternatively, if the first component is due to outwardly mixed 56Ni then our observations are consistent with the asymmetric ejection of a small amount of mass (~ 0.05 M_⊙) ahead of the bulk explosion. Current models for the collision of a SN shock with a binary companion cannot reproduce both the timescale and luminosity of the early emission in SN2013ge. Finally, we find that the spectra of the first component of SN2013ge are similar to those of the rapidly-declining SN2002bj.
    Preview · Article · Jul 2015
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    ABSTRACT: The Fermi Gamma-ray Space Telescope has greatly expanded the number and energy window of observations of gamma-ray bursts (GRBs). However, the coarse localizations of tens to a hundred square degrees provided by the Fermi GRB Monitor instrument have posed a formidable obstacle to locating the bursts' host galaxies, measuring their redshifts, and tracking their panchromatic afterglows. We have built a target-of-opportunity mode for the intermediate Palomar Transient Factory in order to perform targeted searches for Fermi afterglows. Here, we present the results of one year of this program: 8 afterglow discoveries out of 35 searches. Two of the bursts with detected afterglows (GRBs 130702A and 140606B) were at low redshift (z = 0.145 and 0.384, respectively) and had spectroscopically confirmed broad-line Type Ic supernovae. We present our broadband follow-up including spectroscopy as well as X-ray, UV, optical, millimeter, and radio observations. We study possible selection effects in the context of the total Fermi and Swift GRB samples. We identify one new outlier on the Amati relation. We find that two bursts are consistent with a mildly relativistic shock breaking out from the progenitor star rather than the ultra-relativistic internal shock mechanism that powers standard cosmological bursts. Finally, in the context of the Zwicky Transient Facility, we discuss how we will continue to expand this effort to find optical counterparts of binary neutron star mergers that may soon be detected by Advanced LIGO and Virgo.
    No preview · Article · Jun 2015
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    ABSTRACT: The IceCube neutrino observatory pursues a follow-up program selecting interesting neutrino events in real-time and issuing alerts for electromagnetic follow-up observations. In March 2012, the most significant neutrino alert during the first three years of operation was issued by IceCube. In the follow-up observations performed by the Palomar Transient Factory (PTF), a Type IIn supernova (SN) PTF12csy was found 0.2∘ away from the neutrino alert direction, with an error radius of 0.54∘. It has a redshift of z=0.0684, corresponding to a luminosity distance of about 300Mpc and the Pan-STARRS1 survey shows that its explosion time was at least 158 days (in host galaxy rest frame) before the neutrino alert, so that a causal connection is unlikely. The a posteriori significance of the chance detection of both the neutrinos and the SN at any epoch is 2.2σ within IceCube's 2011/12 data acquisition season. Also, a complementary neutrino analysis reveals no long-term signal over the course of one year. Therefore, we consider the SN detection coincidental and the neutrinos uncorrelated to the SN. However, the SN is unusual and interesting by itself: It is luminous and energetic, bearing strong resemblance to the SN IIn 2010jl, and shows signs of interaction of the SN ejecta with a dense circumstellar medium. High-energy neutrino emission is expected in models of diffusive shock acceleration, but at a low, non-detectable level for this specific SN. In this paper, we describe the SN PTF12csy and present both the neutrino and electromagnetic data, as well as their analysis.
    Full-text · Article · Jun 2015 · The Astrophysical Journal
  • E. Y. Hsiao · Y. Cao · S. R. Kulkarni · D. A. Perley · J. Surace · M. M. Kasliwal
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    ABSTRACT: We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C i lines, and the C iλ1.0693 μm line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C ii counterparts were found, even though the optical spectroscopic time series began early and is densely cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C i compared to the weaker optical C ii appears to be general in SNe Ia. iPTF13ebh is a fast decliner with Δm15(B) = 1.79 ± 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categorized as a “transitional” event, on the fast-declining end of normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh shows NIR spectroscopic properties that are distinct from both the normal and subluminous/91bg-like classes, bridging the observed characteristics of the two classes. These NIR observations suggest that composition and density of the inner core are similar to that of 91bg-like events, and that it has a deep-reaching carbon burning layer that is not observed in more slowly declining SNe Ia. There is also a substantial difference between the explosion times inferred from the early-time light curve and the velocity evolution of the Si iiλ0.6355 μm line, implying a long dark phase of ~4 days.
    No preview · Article · Jun 2015
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    ABSTRACT: Type Ia supernovae are destructive explosions of carbon oxygen white dwarfs. Although they are used empirically to measure cosmological distances, the nature of their progenitors remains mysterious, One of the leading progenitor models, called the single degenerate channel, hypothesizes that a white dwarf accretes matter from a companion star and the resulting increase in its central pressure and temperature ignites thermonuclear explosion. Here we report observations of strong but declining ultraviolet emission from a Type Ia supernova within four days of its explosion. This emission is consistent with theoretical expectations of collision between material ejected by the supernova and a companion star, and therefore provides evidence that some Type Ia supernovae arise from the single degenerate channel.
    Full-text · Article · May 2015 · Nature

Publication Stats

5k Citations
1,461.21 Total Impact Points


  • 2015
    • Hebrew University of Jerusalem
      • Racah Institute of Physics
      Yerushalayim, Jerusalem, Israel
  • 2011-2015
    • Carnegie Institute
      Pasadena, Texas, United States
    • University of California, Berkeley
      • Space Sciences Laboratory
      Berkeley, California, United States
    • University of California, Santa Barbara
      • Department of Physics
      Santa Barbara, California, United States
    • Radboud University Nijmegen
      • Department of Astrophysics
      Nymegen, Gelderland, Netherlands
  • 2005-2015
    • California Institute of Technology
      • • Division of Physics, Mathematics, and Astronomy
      • • Department of Astronomy
      • • Infrared Processing and Analysis Center
      Pasadena, California, United States
    • Pomona College
      • Department of Physics and Astronomy
      Claremont, California, United States
  • 2014
    • AlbaNova University Center
      Tukholma, Stockholm, Sweden
  • 2012-2014
    • Weizmann Institute of Science
      • Nella and Leon Benoziyo Center for Astrophysics
  • 2011-2014
    • Carnegie Institution for Science
      • Department of Terrestrial Magnetism
      Washington, West Virginia, United States
  • 2013
    • Max Planck Institute for Extraterrestrial Physics
      Arching, Bavaria, Germany
    • Las Cumbres Observatory Global Telescope Network
      Goleta, California, United States
  • 2009
    • Swinburne University of Technology
      • Centre for Astrophysics and Supercomputing
      Melbourne, Victoria, Australia
    • The University of Warwick
      • Department of Physics
      Coventry, England, United Kingdom
  • 2006
    • Instituto De Astrofisica De Andalucia
      Granata, Andalusia, Spain
    • Princeton University
      • Department of Astrophysical Sciences
      Princeton, New Jersey, United States