IPAC Image Processing and Data Archiving for the Palomar Transient Factory

Laher, Russ R.; Surace, J.; Grillmair, Carl J.; Ofek, E. O.; Levitan, David; Sesar, Branimir; Eyken, J. C. van; Law, Nicholas M.; Hélou, G.; Hamam, Nouhad; Masci, Frank J.; Mattingly, Sean; Jackson, E. S.; Hacopeans, Eugean; Mi, Wei; Groom, Steven L.; Teplitz, Harry I.; Desai, Vandana; Hale, David; Smith, Roger M.; Walters, Richard; Quimby, R.; Kasliwal, M. M.; Horesh, A.; Bellm, Eric C.; Barlow, Tom A.; Waszczak, A.; Prince, Thomas A.

doi:10.1086/677351

Cited by 85 publications

(67 citation statements)

References 23 publications

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“…Initial processing of the P48 images was conducted by the Infrared Processing and Analysis Center (IPAC; Laher et al 2014). Photometry was extracted using a custom PSF fitting routine (e.g., Sullivan et al 2006), which measures the transient flux after image subtraction (using template images taken before the outburst or long after it faded).…”

Section: Photometrymentioning

confidence: 99%

A CONTINUUM OF H- TO He-RICH TIDAL DISRUPTION CANDIDATES WITH A PREFERENCE FOR E+A GALAXIES

Arcavi

Gal‐Yam

Sullivan

et al. 2014

ApJ

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439

629

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We present the results of a Palomar Transient Factory (PTF) archival search for blue transients that lie in the magnitude range between "normal" core-collapse and superluminous supernovae (i.e., with −21 M R (peak) −19). Of the six events found after excluding all interacting Type IIn and Ia-CSM supernovae, three (PTF09ge, 09axc, and 09djl) are coincident with the centers of their hosts, one (10iam) is offset from the center, and a precise offset cannot be determined for two (10nuj and 11glr). All the central events have similar rise times to the He-rich tidal disruption candidate PS1-10jh, and the event with the best-sampled light curve also has similar colors and power-law decay. Spectroscopically, PTF09ge is He-rich, while PTF09axc and 09djl display broad hydrogen features around peak magnitude. All three central events are in low star formation hosts, two of which are E+A galaxies. Our spectrum of the host of PS1-10jh displays similar properties. PTF10iam, the one offset event, is different photometrically and spectroscopically from the central events, and its host displays a higher star formation rate. Finding no obvious evidence for ongoing galactic nuclei activity or recent star formation, we conclude that the three central transients likely arise from the tidal disruption of a star by a supermassive black hole. We compare the spectra of these events to tidal disruption candidates from the literature and find that all of these objects can be unified on a continuous scale of spectral properties. The accumulated evidence of this expanded sample strongly supports a tidal disruption origin for this class of nuclear transients.

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Section: Photometrymentioning

confidence: 99%

A CONTINUUM OF H- TO He-RICH TIDAL DISRUPTION CANDIDATES WITH A PREFERENCE FOR E+A GALAXIES

Arcavi

Gal‐Yam

Sullivan

et al. 2014

ApJ

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439

629

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“…The IPAC pipeline performs final image reduction, source extraction, and photometric and astrometric calibration (Grillmair et al 2010;Ofek et al 2012;Laher et al 2014). The photometric uncertainty provided by this pipeline is smaller than ∼0.01 mag for R 16 < sources and increases to 0.2 mag at R=20.6.…”

Section: Overview Of the Ptfmentioning

confidence: 99%

The Outer Halo of the Milky Way as Probed by RR Lyr Variables from the Palomar Transient Facility*

Cohen

Sesar

Bahnolzer³

et al. 2017

ApJ

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RR Lyrae stars are ideal massless tracers that can be used to study the total mass and dark matter content of the outer halo of the Milky Way (MW). This is because they are easy to find in the light-curve databases of large stellar surveys and their distances can be determined with only knowledge of the light curve. We present here a sample of 112RR Lyr stars beyond 50 kpc in the outer halo of the MW, excluding the Sgr streams, for which we have obtained moderate-resolution spectra with Deimos on the Keck II Telescope. Four of these have distances exceeding 100 kpc. These were selected from a much larger set of 447candidate RR Lyr stars that were datamined using machine-learning techniques applied to the light curves of variable stars in the Palomar Transient Facility database. The observed radial velocities taken at the phase of the variable corresponding to the time of observation were converted to systemic radial velocities in the Galactic standard of rest. From our sample of 112RR Lyr stars we determine the radial velocity dispersion in the outer halo of the MW to be ∼90 km s −1 at 50kpc, falling to about 65 km s −1 near 100kpc once a small number of major outliers are removed. With reasonable estimates of the completeness of our sample of 447candidates and assuming a spherical halo, we find that the stellar density in the outer halo declines as r 4 -.

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“…PTF searches for transient sources by visiting selected fields of the sky regularly over the duration of several months. The data-reduction procedure is described by Laher et al (2014) and the photometric calibration by Ofek et al (2012aOfek et al ( , 2012b. We only use observations in the R band and neglect <15% of the data in the g band to simplify this analysis.…”

Section: Observationsmentioning

confidence: 99%

Search for Precursor Eruptions Among Type Iib Supernovae

Strotjohann

Ofek

Gal‐Yam

et al. 2015

ApJ

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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 magnitude of −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 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 that 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 (∼2% false-alarm probability). We also report the detection of the progenitor of SN 2011dh that 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.

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IPAC Image Processing and Data Archiving for the Palomar Transient Factory

Cited by 85 publications

References 23 publications

A CONTINUUM OF H- TO He-RICH TIDAL DISRUPTION CANDIDATES WITH A PREFERENCE FOR E+A GALAXIES

A CONTINUUM OF H- TO He-RICH TIDAL DISRUPTION CANDIDATES WITH A PREFERENCE FOR E+A GALAXIES

The Outer Halo of the Milky Way as Probed by RR Lyr Variables from the Palomar Transient Facility*

Search for Precursor Eruptions Among Type Iib Supernovae

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