Recursos de colección

Caltech Authors (143.226 recursos)

Repository of works by Caltech published authors.

Group = IPTF

Mostrando recursos 1 - 20 de 135

  1. Type Ibn Supernovae Show Photometric Homogeneity and Spectral Diversity at Maximum Light

    Hosseinzadeh, Griffin; Cao, Yi; Duggan, Gina; Horesh, Assaf; Kasliwal, Mansi; Laher, Russ; Masci, Frank; Surace, Jason
    Type Ibn supernovae (SNe) are a small yet intriguing class of explosions whose spectra are characterized by low-velocity helium emission lines with little to no evidence for hydrogen. The prevailing theory has been that these are the core-collapse explosions of very massive stars embedded in helium-rich circumstellar material (CSM). We report optical observations of six new SNe Ibn: PTF11rfh, PTF12ldy, iPTF14aki, iPTF15ul, SN 2015G, and iPTF15akq. This brings the sample size of such objects in the literature to 22. We also report new data, including a near-infrared spectrum, on the Type Ibn SN 2015U. In order to characterize the class...

  2. Confined Dense Circumstellar Material Surrounding a Regular Type II Supernova: The Unique Flash-Spectroscopy Event - SN 2013fs

    Yaron, O.; Perley, D. A.; Gal-Yam, A.; Groh, J. H.; Horesh, A.; Ofek, E. O.; Kulkarni, S. R.; Sollerman, J.; Fransson, C.; Rubin, A.; Szabo, P.; Sapir, N.; Taddia, F.; Cenko, S. B.; Valenti, S.; Arcavi, I.; Howell, D. A.; Kasliwal, M. M.; Vreeswijk, P. M.; Khazov, D.; Fox, O. D.; Cao, Y.; Gnat, O.; Kelly, P. L.; Nugent, P. E.; Filippenko, A. V.; Laher, R. R.; Wozniak, P. R.; Lee, W. H.; Rebbapragada, U. D.; Maguire, K.; Sullivan, M.; Soumagnac, M. T.
    With the advent of new wide-field, high-cadence optical transient surveys, our understanding of the diversity of core-collapse supernovae has grown tremendously in the last decade. However, the pre-supernova evolution of massive stars, that sets the physical backdrop to these violent events, is theoretically not well understood and difficult to probe observationally. Here we report the discovery of the supernova iPTF13dqy = SN 2013fs, a mere ~3 hr after explosion. Our rapid follow-up observations, which include multiwavelength photometry and extremely early (beginning at ~6 hr post-explosion) spectra, map the distribution of material in the immediate environment (≾ 10^(15) cm) of the...

  3. Small Near-Earth Asteroids in the Palomar Transient Factory Survey: a Real-Time Streak-detection System

    Waszczak, Adam; Prince, Thomas A.; Laher, Russ; Masci, Frank; Bue, Brian; Rebbapragada, Umaa; Barlow, Tom; Surace, Jason; Helou, George; Kulkarni, Shrinivas
    Near-Earth asteroids (NEAs) in the 1–100 meter size range are estimated to be ~1,000 times more numerous than the ~15,000 currently cataloged NEAs, most of which are in the 0.5–10 kilometer size range. Impacts from 10–100 meter size NEAs are not statistically life-threatening, but may cause significant regional damage, while 1–10 meter size NEAs with low velocities relative to Earth are compelling targets for space missions. We describe the implementation and initial results of a real-time NEA-discovery system specialized for the detection of small, high angular rate (visually streaked) NEAs in Palomar Transient Factory (PTF) images. PTF is a 1.2-m...

  4. Preparing for Advanced LIGO: A Star–Galaxy Separation Catalog for the Palomar Transient Factory

    Miller, A. A.; Kulkarni, M. K.; Cao, Y.; Laher, R. R.; Masci, F. J.; Surace, J. A.
    The search for fast optical transients, such as the expected electromagnetic counterparts to binary neutron star mergers, is riddled with false positives (FPs) ranging from asteroids to stellar flares. While moving objects are readily rejected via image pairs separated by ~1 hr, stellar flares represent a challenging foreground, significantly outnumbering rapidly evolving explosions. Identifying stellar sources close to and fainter than the transient detection limit can eliminate these FPs. Here, we present a method to reliably identify stars in deep co-adds of Palomar Transient Factory (PTF) imaging. Our machine-learning methodology utilizes the random forest (RF) algorithm, which is trained using...

  5. PTF1 J082340.04+081936.5: A Hot Subdwarf B Star with a Low-mass White Dwarf Companion in an 87-minute Orbit

    Kupfer, Thomas; van Roestel, Jan; Brooks, Jared; Geier, Stephan; Marsh, Tom R.; Groot, Paul J.; Bloemen, Steven; Prince, Thomas A.; Bellm, Eric; Heber, Ulrich; Bildsten, Lars; Miller, Adam A.; Dyer, Martin J.; Dhillon, Vik S.; Green, Matthew; Irawati, Puji; Laher, Russ; Littlefair, Stuart P.; Shupe, David L.; Steidel, Charles C.; Rattansoon, Somsawat; Pettini, Max
    We present the discovery of the hot subdwarf B star (sdB) binary PTF1 J082340.04+081936.5. The system has an orbital period of P_(orb) = 87.49668(1) minutes (0.060761584(10) days), making it the second-most compact sdB binary known. The light curve shows ellipsoidal variations. Under the assumption that the sdB primary is synchronized with the orbit, we find a mass of M_(sdB) = 0.45_(-0.07)^(+0.09) M_⊙, a companion white dwarf mass of M_(WD) = 0.46_(-0.09)^(+0.12) M_⊙, and a mass ratio of q = M_(WD)/M_(sdB) = 1.03_(-0.08)^(+0.10). The future evolution was calculated using the MESA stellar evolution code. Adopting a canonical sdB mass of M_(sdB)...

  6. iPTF Discovery of the Rapid “Turn-on” of a Luminous Quasar

    Gezari, S.; Hung, T.; Cenko, S. B.; Blagorodnova, N.; Yan, Lin; Kulkarni, S. R.; Mooley, K.; Kong, A. K. H.; Cantwell, T. M.; Yu, P. C.; Cao, Y.; Fremling, C.; Neill, J. D.; Ngeow, C.-C.; Nugent, P. E.; Wozniak, P.
    We present a radio-quiet quasar at z = 0.237 discovered "turning on" by the intermediate Palomar Transient Factory (iPTF). The transient, iPTF 16bco, was detected by iPTF in the nucleus of a galaxy with an archival Sloan Digital Sky Survey spectrum with weak narrow-line emission characteristic of a low-ionization nuclear emission-line region (LINER). Our follow-up spectra show the dramatic appearance of broad Balmer lines and a power-law continuum characteristic of a luminous (L_(bol) ≈ 10^(45) erg s^(−1)) type 1 quasar 12 yr later. Our photometric monitoring with PTF from 2009–2012 and serendipitous X-ray observations from the XMM-Newton Slew Survey in...

  7. On the Early-time Excess Emission in Hydrogen-poor Superluminous Supernovae

    Vreeswijk, Paul M.; Perley, Daniel A.; Kasliwal, Mansi M.; Cao, Yi; Lunnan, Ragnhild; Kulkarni, Shrinivas R.; Yan, Lin; Laher, Russ
    We present the light curves of the hydrogen-poor superluminous supernovae (SLSNe I) PTF 12dam and iPTF 13dcc, discovered by the (intermediate) Palomar Transient Factory. Both show excess emission at early times and a slowly declining light curve at late times. The early bump in PTF 12dam is very similar in duration (~10 days) and brightness relative to the main peak (2–3 mag fainter) compared to that observed in other SLSNe I. In contrast, the long-duration (>30 days) early excess emission in iPTF 13dcc, whose brightness competes with that of the main peak, appears to be of a different nature. We...

  8. Common Envelope Ejection for a Luminous Red Nova in M101

    Blagorodnova, N.; Kotak, R.; Polshaw, J.; Kasliwal, M. M.; Cao, Y.; Cody, A. M.; Doran, G. B.; Elias-Rosa, N.; Fraser, M.; Fremling, C.; Gonzalez-Fernandez, C.; Harmanen, J.; Jencson, J.; Kankare, E.; Kudritzki, R.-P.; Kulkarni, S. R.; Magnier, E.; Manulis, I.; Masci, F. J.; Mattila, S.; Nugent, P.; Ochner, P.; Pastorello, A.; Reynolds, T.; Smith, K.; Sollerman, J.; Taddia, F.; Terreran, G.; Tomasella, L.; Turatto, M.; Vreeswijk, P. M.; Wozniak, P.; Zaggia, S.
    We present the results of optical, near-infrared, and mid-infrared observations of M101 OT2015-1 (PSN J14021678+5426205), a luminous red transient in the Pinwheel galaxy (M101), spanning a total of 16 years. The light curve showed two distinct peaks with absolute magnitudes M_r ≤ -12.4 and M_r ≃ -12, on 2014 November 11 and 2015 February 17, respectively. The spectral energy distributions during the second maximum show a cool outburst temperature of ≈ 3700 K and low expansion velocities (≈-300 km s^(−1)) for the H i, Ca ii, Ba ii, and K i lines. From archival data spanning 15–8 years before the...

  9. The Palomar Transient Factory and RR Lyrae: The Metallicity–Light Curve Relation Based on ab-type RR Lyrae in the Kepler Field

    Ngeow, Chow-Choong; Yu, Po-Chieh; Bellm, Eric; Yang, Ting-Chang; Chang, Chan-Kao; Miller, Adam; Laher, Russ; Surace, Jason; Ip, Wing-Huen
    The wide-field synoptic sky surveys, known as the Palomar Transient Factory (PTF) and the intermediate Palomar Transient Factory (iPTF), will accumulate a large number of known and new RR Lyrae. These RR Lyrae are good tracers to study the substructure of the Galactic halo if their distance, metallicity, and galactocentric velocity can be measured. Candidates of halo RR Lyrae can be identified from their distance and metallicity before requesting spectroscopic observations for confirmation. This is because both quantities can be obtained via their photometric light curves, because the absolute V-band magnitude for RR Lyrae is correlated with metallicity, and the...

  10. A population of short-period variable quasars from PTF as supermassive black hole binary candidates

    Charisi, M.; Bartos, I.; Haiman, Z.; Price-Whelan, A. M.; Graham, M. J.; Bellm, E. C.; Laher, R. R.; Márka, S.
    Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circum-binary discs predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. As a result, SMBHBs may be recognized by the periodic modulation of their brightness. We conducted a statistical search for periodic variability in a sample of 35 383 spectroscopically confirmed quasars in the photometric data base of the Palomar Transient Factory (PTF). We analysed Lomb–Scargle periodograms and assessed the significance of our findings by modelling...

  11. Large Super-Fast Rotator Hunting Using the Intermediate Palomar Transient Factory

    Chang, Chan-Kao; Lin, Hsing-Wen; Ip, Wing-Huen; Prince, Thomas A.; Kulkarni, Shrinivas R.; Levitan, David; Laher, Russ; Surace, Jason
    In order to look for large super-fast rotators, in late 2014 and early 2015, five dedicated surveys covering ~188 deg2 in the ecliptic plane have been carried out in the R-band, with ~10 minute cadence using the intermediate Palomar Transient Factory. Among 1029 reliable rotation periods obtained from the surveys, we discovered 1 new large super-fast rotator, (40511) 1999 RE88, and 18 other candidates. (40511) 1999 RE88 is an S-type inner main-belt asteroid with a diameter of D = 1.9 ± 0.3 km, a rotation period of P = 1.96 ± 0.01 hr, and a light curve amplitude of Δm...

  12. SN2002es-like Supernovae from Different Viewing Angles

    Cao, Yi; Kulkarni, S. R.; Gal-Yam, Avishay; Papadogiannakis, S.; Nugent, P. E.; Masci, Frank J.; Bue, Brian D.
    In this article, we compare optical light curves of two SN2002es-like Type Ia supernovae (SNe), iPTF14atg and iPTF14dpk, from the intermediate Palomar Transient Factory. Although the two light curves resemble each other around and after maximum, they show distinct early-phase rise behavior in the r-band. On the one hand, iPTF14atg revealed a slow and steady rise that lasted for 22 days with a mean rise rate of 0.2–0.3 mag day^(-1), before it reached the R-band peak (−18.05 mag). On the other hand, iPTF14dpk rose rapidly to −17 mag within a day of discovery with a rise rate > 1.8 mag...

  13. Time-varying sodium absorption in the Type Ia supernova 2013gh

    Ferretti, R.; Amanullah, R.; Goobar, A.; Johansson, J.; Vreeswijk, P. M.; Butler, R. P.; Cao, Y.; Cenko, S. B.; Doran, G.; Filippenko, A. V.; Freeland, E.; Hosseinzadeh, G.; Howell, D. A.; Lundqvist, P.; Mattila, S.; Nordin, J.; Nugent, P. E.; Petrushevska, T.; Valenti, S.; Vogt, S. S.; Wozniak, P.
    Context. 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 Na I D or Ca II 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. Aims. To date, there are few known cases of time-varying Na I D absorption in SNe Ia, all of which...

  14. iPTF15dtg: a double-peaked Type Ic supernova from a massive progenitor

    Taddia, F.; Fremling, C.; Sollerman, J.; Corsi, A.; Gal-Yam, A.; Karamehmetoglu, E.; Lunnan, R.; Bue, B.; Ergon, M.; Kasliwal, M.; Vreeswijk, P. M.; Wozniak, P. R.
    Context. Type Ic supernovae (SNe Ic) arise from the core-collapse of H- (and He-) poor stars, which could either be single Wolf-Rayet (WR) stars or lower-mass stars stripped of their envelope by a companion. Their light curves are radioactively powered and usually show a fast rise to peak (~10−15 d), without any early (in the first few days) emission bumps (with the exception of broad-lined SNe Ic) as sometimes seen for other types of stripped-envelope SNe (e.g., Type IIb SN 1993J and Type Ib SN 2008D). Aims. We have studied iPTF15dtg, a spectroscopically normal SN Ic with an early excess in...

  15. Localization and Broadband Follow-up of the Gravitational-wave Transient GW150914

    Abbott, B. P.; Abbott, R.; Abernathy, M. R.; Adhikari, R. X.; Anderson, S. B.; Arai, K.; Araya, M. C.; Barayoga, J. C.; Barish, B. C.; Berger, B. K.; Billingsley, G.; Blackburn, J. K.; Bork, R.; Brooks, A. F.; Cahillane, C.; Callister, T.; Cepeda, C. B.; Chakraborty, R.; Chalermsongsak, T.; Couvares, P.; Coyne, D. C.; Dergachev, V.; Drever, R. W. P.; Ehrens, P.; Etzel, T.; Gossan, S. E.; Gushwa, K. E.; Gustafson, E. K.; Hall, E. D.; Heptonstall, A. W.; Hodge, K. A.; Isi, M.; Kanner, J. B.; Kells, W.; Kondrashov, V.; Korth, W. Z.; Kozak, D. B.; Lazzarini, A.; Li, T. G. F.; Mageswaran, M.; Maros, E.; Martynov, D. V.; Marx, J. N.; McIntyre, G.; McIver, J.; Meshkov, S.; Pedraza, M.; Perreca, A.; Price , L. R.; Quintero, E. A.; Reitze, D. H.; Robertson, N. A.; Rollins, J. G.; Sachdev, S.; Sanchez, E. J.; Schmidt, P.; Shao, Z.; Singer, A.; Smith, N. D.; Smith, R. J. E.; Taylor, R.; Thirugnanasambandam, M. P.; Torrie, C. I.; Vajente, G.; Vass, S.; Wallace, L.; Weinstein, A. J.; Williams, R. D.; Wipf, C. C.; Yamamoto, H.; Zhang, L.; Zucker, M. E.; Zweizig, J.; Chen, Yanbei; Engels, W.; Thorne, K. S.; Kasliwal, M. M.; Cao, Y.; Duggan, G.; Kulkarni, S. R.; Miller, A. A.; Barlow, T.; Bellm, E.; Cook, D.; Prince, T.; Kupfer, T.; Laher, R.; Masci, F.; Surace, J.
    A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the...

  16. Photometric variability of candidate white dwarf binary systems from Palomar Transient Factory archival data

    Kao, Wil; Kaplan, David L.; Prince, Thomas A.; Tang, Sumin; Ene, Irina; Kim, Kyu Bin; Levitan, David; Kulkarni, Shrinivas R.; Laher, Russ R.
    We present a sample of 59 periodic variables from the Palomar Transient Factory, selected from published catalogues of white dwarf (WD) candidates. The variability can likely be attributed to ellipsoidal variation of the tidally distorted companion induced by the gravity of the primary (WD or hot subdwarf) or to the reflection of hot emission by a cooler companion. We searched 11 311 spectroscopically or photometrically selected WD candidates from three hot star/WD catalogues, using the Lomb–Scargle periodogram to single out promising sources. We present period estimates for the candidates, 45 of which were not previously identified as periodic variables, and find...

  17. Hα Variability in PTFO8-8695 and the Possible Direct Detection of Emission from a 2 Million Year Old Evaporating Hot Jupiter

    Johns-Krull, Christopher M.; Prato, Lisa; McLane, Jacob N.; Ciardi, David R.; van Eyken, Julian C.; Chen, Wei; Stauffer, John R.; Beichman, Charles A.; Frazier, Sarah A.; Boden, Andrew F.; Morales-Calderón, María; Rebull, Luisa M.
    We use high time cadence, high spectral resolution optical observations to detect excess Hα emission from the 2–3 Myr old weak-lined T Tauri star PTFO 8-8695. This excess emission appears to move in velocity as expected if it were produced by the suspected planetary companion to this young star. The excess emission is not always present, but when it is, the predicted velocity motion is often observed. We have considered the possibility that the observed excess emission is produced by stellar activity (flares), accretion from a disk, or a planetary companion; we find the planetary companion to be the most...

  18. Host-Galaxy Properties of 32 Low-Redshift Superluminous Supernovae from the Palomar Transient Factory

    Perley, D. A.; Quimby, R. M.; Yang, L.; Vreeswijk, P. M.; De Cia, A.; Lunnan, R.; Gal-Yam, A.; Yaron, O.; Filippenko, A. V.; Graham, M. L.; Laher, R.; Nugent, P. E.
    We present ultraviolet through near-infrared photometry and spectroscopy of the host galaxies of all superluminous supernovae (SLSNe) discovered by the Palomar Transient Factory prior to 2013 and derive measurements of their luminosities, star formation rates, stellar masses, and gas-phase metallicities. We find that Type I (hydrogen-poor) SLSNe (SLSNe I) are found almost exclusively in low-mass (M_* < 2 x 10^9 M_⊙) and metal-poor (12 + log_(10)[O/H] < 8.4) galaxies. We compare the mass and metallicity distributions of our sample to nearby galaxy catalogs in detail and conclude that the rate of SLSNe I as a fraction of all SNe is...

  19. Intermediate Palomar Transient Factory: Realtime Image Subtraction Pipeline

    Cao, Yi; Nugent, Peter E.; Kasliwal, Mansi M.
    A fast-turnaround pipeline for realtime data reduction plays an essential role in discovering and permitting follow-up observations to young supernovae and fast-evolving transients in modern time-domain surveys. In this paper, we present the realtime image subtraction pipeline in the intermediate Palomar Transient Factory. By using high-performance computing, efficient databases, and machine-learning algorithms, this pipeline manages to reliably deliver transient candidates within 10 minutes of images being taken. Our experience in using high-performance computing resources to process big data in astronomy serves as a trailblazer to dealing with data from large-scale time-domain facilities in the near future.

  20. Disappearance of the Progenitor of Supernova iPTF13bvn

    Folatelli, Gastón; Van Dyk, Schuyler D.; Kuncarayakti, Hanindyo; Maeda, Keiichi; Bersten, Melina C.; Nomoto, Ken’ichi; Pignata, Giuliano; Hamuy, Mario; Quimby, Robert M.; Zheng, Weikang; Filippenko, Alexei V.; Clubb, Kelsey I.; Smith, Nathan; Elias-Rosa, Nancy; Foley, Ryan J.; Miller, Adam A.
    Supernova (SN) iPTF13bvn in NGC 5806 was the first Type Ib SN to have been tentatively associated with a progenitor in pre-explosion images. We performed deep ultraviolet (UV) and optical Hubble Space Telescope observations of the SN site ~740 days after explosion. We detect an object in the optical bands that is fainter than the pre-explosion object. This dimming is likely not produced by dust absorption in the ejecta; thus, our finding confirms the connection of the progenitor candidate with the SN. The object in our data is likely dominated by the fading SN, implying that the pre-SN flux is...

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