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Caltech Authors (162.548 recursos)

Repository of works by Caltech published authors.

Group = IPTF

Mostrando recursos 81 - 100 de 285

  1. Absence of Fast-moving Iron in an Intermediate Type Ia Supernova between Normal and Super-Chandrasekhar

    Cao, Yi; Johansson, J.; Nugent, Peter E.; Goobar, A.; Nordin, Jakob; Kulkarni, S. R.; Cenko, S. Bradley; Fox, Ori; Kasliwal, Mansi M.; Fremling, C.; Amanullah, R.; Hsiao, E. Y.; Perley, D. A.; Bue, Brian D.; Masci, Frank J.; Lee, William H.; Chotard, Nicolas
    In this paper, we report observations of a peculiar SN Ia iPTF13asv (a.k.a., SN2013cv) from the onset of the explosion to months after its peak. The early-phase spectra of iPTF13asv show an absence of iron absorption, indicating that synthesized iron elements are confined to low-velocity regions of the ejecta, which, in turn, implies a stratified ejecta structure along the line of sight. Our analysis of iPTF13asv's light curves and spectra shows that it is an intermediate case between normal and super-Chandrasekhar events. On the one hand, its light curve shape (B-band Δm_(15) = 1.03 ± 0.01) and overall spectral features...

  2. Absence of Fast-moving Iron in an Intermediate Type Ia Supernova between Normal and Super-Chandrasekhar

    Cao, Yi; Johansson, J.; Nugent, Peter E.; Goobar, A.; Nordin, Jakob; Kulkarni, S. R.; Cenko, S. Bradley; Fox, Ori; Kasliwal, Mansi M.; Fremling, C.; Amanullah, R.; Hsiao, E. Y.; Perley, D. A.; Bue, Brian D.; Masci, Frank J.; Lee, William H.; Chotard, Nicolas
    In this paper, we report observations of a peculiar SN Ia iPTF13asv (a.k.a., SN2013cv) from the onset of the explosion to months after its peak. The early-phase spectra of iPTF13asv show an absence of iron absorption, indicating that synthesized iron elements are confined to low-velocity regions of the ejecta, which, in turn, implies a stratified ejecta structure along the line of sight. Our analysis of iPTF13asv's light curves and spectra shows that it is an intermediate case between normal and super-Chandrasekhar events. On the one hand, its light curve shape (B-band Δm_(15) = 1.03 ± 0.01) and overall spectral features...

  3. Radio observations of a sample of broad-lined type Ic supernovae discovered by PTF/iPTF: A search for relativistic explosions

    Corsi, A.; Gal-Yam, A.; Kulkarni, S. R.; Frail, D. A.; Mazzali, P. A.; Cenko, S. B.; Kasliwal, M. M.; Cao, Y.; Horesh, A.; Palliyaguru, N.; Perley, D. A.; Laher, R. R.; Taddia, F.; Leloudas, G.; Maguire, K.; Nugent, P. E.; Sollerman, J.; Sullivan, M.
    Long duration γ-ray bursts are a rare subclass of stripped-envelope core-collapse supernovae (SNe) that launch collimated relativistic outflows (jets). All γ-ray-burst-associated SNe are spectroscopically Type Ic, with broad-lines, but the fraction of broad-lined SNe Ic harboring low-luminosity γ-ray bursts remains largely unconstrained. Some SNe should be accompanied by off-axis γ-ray burst jets that initially remain invisible, but then emerge as strong radio sources (as the jets decelerate). However, this critical prediction of the jet model for γ-ray bursts has yet to be verified observationally. Here, we present K. G. Jansky Very Large Array observations of 15 broad-lined SNe of Type...

  4. Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material around <10-Day-Old Type II Supernovae

    Khazov, D.; Kulkarni, S. R.; Kasliwal, M. M.; Cao, Y.; Perley, D.; Laher, R. R.; Surace, J.
    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤ 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...

  5. Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material around <10-Day-Old Type II Supernovae

    Khazov, D.; Kulkarni, S. R.; Kasliwal, M. M.; Cao, Y.; Perley, D.; Laher, R. R.; Surace, J.
    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤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 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events...

  6. The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection

    Myers, Adam D.; Kulkarni, Shrinivas R.; Miller, Adam A.; Laher, Russ; Surace, Jason; Levitan, David
    As part of the Sloan Digital Sky Survey (SDSS) IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will improve measurements of the cosmological distance scale by applying the Baryon Acoustic Oscillation (BAO) method to quasar samples. eBOSS will adopt two approaches to target quasars over 7500 deg^2. First, a "CORE" quasar sample will combine the optical selection in ugriz using a likelihood-based routine called XDQSOz, with a mid-IR-optical color cut. eBOSS CORE selection (to g < 22 or r < 22) should return ~70 deg^(−2) quasars at redshifts 0.9 < z < 2.2 and ~7 deg^(−2)z > 2.1 quasars. Second,...

  7. The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection

    Myers, Adam D.; Kulkarni, Shrinivas R.; Miller, Adam A.; Laher, Russ; Surace, Jason; Levitan, David
    As part of the Sloan Digital Sky Survey (SDSS) IV the extended Baryon Oscillation Spectroscopic Survey (eBOSS) will improve measurements of the cosmological distance scale by applying the Baryon Acoustic Oscillation (BAO) method to quasar samples. eBOSS will adopt two approaches to target quasars over 7500 deg^2. First, a "CORE" quasar sample will combine the optical selection in ugriz using a likelihood-based routine called XDQSOz, with a mid-IR-optical color cut. eBOSS CORE selection (to g < 22 or r < 22) should return ~70 deg^(−2) quasars at redshifts 0.9 < z < 2.2 and ~7 deg^(−2)z > 2.1 quasars. Second,...

  8. The detection rate of early UV emission from supernovae: A dedicated GALEX/PTF survey and calibrated theoretical estimates

    Ganot, Noam; Gal-Yam, Avishay; Ofek, Eran O.; Sagiv, Ilan; Waxman, Eli; Lapid, Ofer; Kulkarni, Shrinivas R.; Ben-Ami, Sagi; Kasliwal, Mansi M.; Chelouche, Doron; Rafter, Stephen; Behar, Ehud; Laor, Ari; Poznanski, Dovi; Nakar, Udi; Maoz, Dan; Trakhtenbrot, Benny; Neill, James D.; Barlow, Thomas A.; Martin, D. Christopher; Gezari, Suvi; Arcavi, Iair; Bloom, Joshua S.; Nugent, Peter E.; Sullivan, Mark
    The radius and surface composition of an exploding massive star, as well as the explosion energy per unit mass, can be measured using early UV observations of core collapse supernovae (SNe). We present the first results from a simultaneous GALEX/PTF search for early UV emission from SNe. Six Type II SNe and one Type II superluminous SN (SLSN-II) are clearly detected in the GALEX NUV data. We compare our detection rate with theoretical estimates based on early, shock-cooling UV light curves calculated from models that fit existing Swift and GALEX observations well, combined with volumetric SN rates. We find that...

  9. The detection rate of early UV emission from supernovae: A dedicated GALEX/PTF survey and calibrated theoretical estimates

    Ganot, Noam; Gal-Yam, Avishay; Ofek, Eran O.; Sagiv, Ilan; Waxman, Eli; Lapid, Ofer; Kulkarni, Shrinivas R.; Ben-Ami, Sagi; Kasliwal, Mansi M.; Chelouche, Doron; Rafter, Stephen; Behar, Ehud; Laor, Ari; Poznanski, Dovi; Nakar, Udi; Maoz, Dan; Trakhtenbrot, Benny; Neill, James D.; Barlow, Thomas A.; Martin, D. Christopher; Gezari, Suvi; Arcavi, Iair; Bloom, Joshua S.; Nugent, Peter E.; Sullivan, Mark
    The radius and surface composition of an exploding massive star, as well as the explosion energy per unit mass, can be measured using early UV observations of core collapse supernovae (SNe). We present the first results from a simultaneous GALEX/PTF search for early UV emission from SNe. Six Type II SNe and one Type II superluminous SN (SLSN-II) are clearly detected in the GALEX NUV data. We compare our detection rate with theoretical estimates based on early, shock-cooling UV light curves calculated from models that fit existing Swift and GALEX observations well, combined with volumetric SN rates. We find that...

  10. Tests of the planetary hypothesis for PTFO 8-8695b

    Yu, Liang; Winn, Joshua N.; Gillon, Michaël; Albrecht, Simon; Rappaport, Saul; Bieryla, Allyson; Dai, Fei; Delrez, Laetitia; Hillenbrand, Lynne; Holman, Matthew J.; Howard, Andrew W.; Huang, Chelsea X.; Isaacson, Howard T.; Jehin, Emmanuel; Lendl, Monika; Montet, Benjamin T.; Muirhead, Philip; Sanchis-Ojeda, Roberto; Triaud, Amaury H. M. J.
    The T Tauri star PTFO 8-8695 exhibits periodic fading events that have been interpreted as the transits of a giant planet on a precessing orbit. Here we present three tests of the planet hypothesis. First, we sought evidence for the secular changes in light-curve morphology that are predicted to be a consequence of orbital precession. We observed 28 fading events spread over several years and did not see the expected changes. Instead, we found that the fading events are not strictly periodic. Second, we attempted to detect the planet's radiation, based on infrared observations spanning the predicted times of occultations....

  11. Tests of the planetary hypothesis for PTFO 8-8695b

    Yu, Liang; Winn, Joshua N.; Gillon, Michaël; Albrecht, Simon; Rappaport, Saul; Bieryla, Allyson; Dai, Fei; Delrez, Laetitia; Hillenbrand, Lynne; Holman, Matthew J.; Howard, Andrew W.; Huang, Chelsea X.; Isaacson, Howard T.; Jehin, Emmanuel; Lendl, Monika; Montet, Benjamin T.; Muirhead, Philip; Sanchis-Ojeda, Roberto; Triaud, Amaury H. M. J.
    The T Tauri star PTFO 8-8695 exhibits periodic fading events that have been interpreted as the transits of a giant planet on a precessing orbit. Here we present three tests of the planet hypothesis. First, we sought evidence for the secular changes in light-curve morphology that are predicted to be a consequence of orbital precession. We observed 28 fading events spread over several years and did not see the expected changes. Instead, we found that the fading events are not strictly periodic. Second, we attempted to detect the planet's radiation, based on infrared observations spanning the predicted times of occultations....

  12. The hydrogen-poor superluminous supernova iPTF 13ajg and its host galaxy in absorption and emission

    Vreeswuk, Paul M.; Perley, Daniel A.; Cao, Yi; Kulkarni, Shrinivas R.; Laher, Russ; Surace, Jason
    We present imaging and spectroscopy of a hydrogen-poor superluminous supernova (SLSN) discovered by the intermediate Palomar Transient Factory, iPTF 13ajg. At a redshift of z = 0.7403, derived from narrow absorption lines, iPTF 13ajg peaked at an absolute magnitude of M_(u,AB) = –22.5, one of the most luminous supernovae to date. The observed bolometric peak luminosity of iPTF 13ajg is 3.2 × 10^(44) erg s^(–1), while the estimated total radiated energy is 1.3 × 10^(51) erg. We detect narrow absorption lines of Mg I, Mg II, and Fe II, associated with the cold interstellar medium in the host galaxy, at...

  13. Constraints on the origin of the first light from SN2014J

    Goobar, A.; Kromer, M.; Siverd, R.; Stassun, K. G.; Pepper, J.; Amanullah, R.; Kasliwal, M.; Sollerman, J.; Taddia, F.
    We study the very early lightcurve of supernova 2014J (SN2014J) using the high-cadence broad-band imaging data obtained by the Kilodegree Extremely Little Telescope (KELT), which fortuitously observed M 82 around the time of the explosion, starting more than two months prior to detection, with up to 20 observations per night. These observations are complemented by observations in two narrow-band filters used in an Hα survey of nearby galaxies by the intermediate Palomar Transient Factory (iPTF) that also captured the first days of the brightening of the SN. The evolution of the lightcurves is consistent with the expected signal from the cooling of shock heated material of large scale...

  14. Constraints on the origin of the first light from SN2014J

    Goobar, A.; Kromer, M.; Siverd, R.; Stassun, K. G.; Pepper, J.; Amanullah, R.; Kasliwal, M.; Sollerman, J.; Taddia, F.
    We study the very early lightcurve of supernova 2014J (SN2014J) using the high-cadence broad-band imaging data obtained by the Kilodegree Extremely Little Telescope (KELT), which fortuitously observed M 82 around the time of the explosion, starting more than two months prior to detection, with up to 20 observations per night. These observations are complemented by observations in two narrow-band filters used in an Hα survey of nearby galaxies by the intermediate Palomar Transient Factory (iPTF) that also captured the first days of the brightening of the SN. The evolution of the lightcurves is consistent with the expected signal from the cooling of shock heated material of large scale...

  15. Exploring the spectral diversity of low-redshift Type Ia supernovae using the Palomar Transient Factory

    Maguire, K.; Sullivan, M.; Pan, Y.-C.; Gal-Yam, A.; Hook, I. M.; Howell, D. A.; Nugent, P. E.; Mazzali, P.; Chotard, N.; Clubb, K. I.; Filippenko, A. V.; Kasliwal, M. M.; Kandrashoff, M. T.; Poznanski, D.; Saunders, C. M.; Silverman, J. M.; Walker, E.; Xu, D.
    We present an investigation of the optical spectra of 264 low-redshift (z < 0.2) Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory, an untargeted transient survey. We focus on velocity and pseudo-equivalent width measurements of the Si ii 4130, 5972, and 6355Å lines, as well those of the Ca ii near-infrared (NIR) triplet, up to +5 days relative to the SN B-band maximum light.We find that a high-velocity component of the Ca ii NIR triplet is needed to explain the spectrum in ∼ 95 per cent of SNe Ia observed before −5 days, decreasing to ∼ 80 per cent at maximum. The average...

  16. Exploring the spectral diversity of low-redshift Type Ia supernovae using the Palomar Transient Factory

    Maguire, K.; Sullivan, M.; Pan, Y.-C.; Gal-Yam, A.; Hook, I. M.; Howell, D. A.; Nugent, P. E.; Mazzali, P.; Chotard, N.; Clubb, K. I.; Filippenko, A. V.; Kasliwal, M. M.; Kandrashoff, M. T.; Poznanski, D.; Saunders, C. M.; Silverman, J. M.; Walker, E.; Xu, D.
    We present an investigation of the optical spectra of 264 low-redshift (z < 0.2) Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory, an untargeted transient survey. We focus on velocity and pseudo-equivalent width measurements of the Si ii 4130, 5972, and 6355Å lines, as well those of the Ca ii near-infrared (NIR) triplet, up to +5 days relative to the SN B-band maximum light.We find that a high-velocity component of the Ca ii NIR triplet is needed to explain the spectrum in ∼ 95 per cent of SNe Ia observed before −5 days, decreasing to ∼ 80 per cent at maximum. The average...

  17. The Detection of a Type IIn Supernova in Optical Follow-up Observations of IceCube Neutrino Events

    Aartsen, M. G.; Kulkarni, Shrinivas R.; Perley, Daniel A.; Barlow, Tom; Kasliwal, M. M.
    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...

  18. Search for precursor eruptions among Type IIb supernovae

    Strotjohann, Nora L.; Ofek, Eran O.; Gal-Yam, Avishay; Sullivan, Mark; Kulkarni, Shrinivas R.; Shaviv, Nir J.; Fremling, Christoffer; Kasliwal, Mansi M.; Nugent, Peter E.; Cao, Yi; Arcavi, Iair; Sollerman, Jesper; Filippenko, Alexei V.; Yaron, Ofer; Laher, Russ; Surace, Jason
    The progenitor stars of several Type IIb supernovae (SNe) show indications of 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 SNe IIb 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, SNe IIb have on average <0.86 precursors as bright as an absolute R-band...

  19. Search for precursor eruptions among Type IIb supernovae

    Strotjohann, Nora L.; Ofek, Eran O.; Gal-Yam, Avishay; Sullivan, Mark; Kulkarni, Shrinivas R.; Shaviv, Nir J.; Fremling, Christoffer; Kasliwal, Mansi M.; Nugent, Peter E.; Cao, Yi; Arcavi, Iair; Sollerman, Jesper; Filippenko, Alexei V.; Yaron, Ofer; Laher, Russ; Surace, Jason
    The progenitor stars of several Type IIb supernovae (SNe) show indications of 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 SNe IIb 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, SNe IIb have on average <0.86 precursors as bright as an absolute R-band...

  20. Search for precursor eruptions among Type IIb supernovae

    Strotjohann, Nora L.; Ofek, Eran O.; Gal-Yam, Avishay; Sullivan, Mark; Kulkarni, Shrinivas R.; Shaviv, Nir J.; Fremling, Christoffer; Kasliwal, Mansi M.; Nugent, Peter E.; Cao, Yi; Arcavi, Iair; Sollerman, Jesper; Filippenko, Alexei V.; Yaron, Ofer; Laher, Russ; Surace, Jason
    The progenitor stars of several Type IIb supernovae (SNe) show indications of 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 SNe IIb 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, SNe IIb have on average <0.86 precursors as bright as an absolute R-band...

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