- What are the progenitors of long-duration GRBs? Are they single or binary, and how does metallicity affect their formation?
- What is the cosmic star-formation rate at very high redshift and how quickly did reionization conclude?
- How can GRBs inform our understanding of the ISM in high-redshift star-forming galaxies?
- What is the origin and frequency of magnetar hyperflares?
- How are the Universe's most luminous transients actually powered?
- What other exotic end-states of massive stellar evolution exist in nature?
- Do all massive stars become unstable in the years preceding the actual supernova explosion? How can early observations better constrain the progenitor population of SNe in general?
Select list of publications, with descriptions:
- Perley, Perley, Hjorth et al. (2014): "Connecting GRBs and ULIRGs: A Sensitive, Unbiased Survey for Radio Emission from Gamma-Ray Burst Host Galaxies at z<2.5 "
The fraction of GRBs actually occur within the Universe's most luminous galaxies provides a tight constraint both on the contribution of very dusty systems to all of cosmic star-formation as well as a constraint on the GRB progenitor and its ability to form in extreme environments. An 80-hour VLA survey shows the fraction to be approximately 15\%, demonstrating that GRBs are able to form in ULIRGs but do not do so ubiquitously. They also seem to occur only in the youngest and most active such systems.
- Perley, Cenko, Corsi et al. (2014): "The Afterglow of GRB 130427A from 1 to 10^16 GHz"
Nearby, luminous GRB 130427A was the brightest GRB in a generation, providing an unprecedented opportunity to study a burst in rigorous detail. We present extensive radio-to-X-ray observations of the afterglow from early through late times and successfully model the entire data set to remarkably good agreement with a simple forward plus reverse shock model. We present evidence that the long-lived emission at GeV energies seen in this and other GRBs is due to the forward shock afterglow.
- Perley and Perley (2013): "Radio Constraints on Heavily-Obscured Star-Formation within Dark Gamma-Ray Burst Host Galaxies"
We present deep radio observations of a subset of the dark GRB host population below, showing that relatively few are bright submillimeter galaxies, and that few dark GRBs occur in extreme starbursts.
- Perley, Levan, Tanvir et al. (2013): "A Population of Massive, Luminous Galaxies Hosting Heavily Dust-Obscured Gamma-Ray Bursts: Implications for the Use of GRBs as Tracers of Cosmic Star Formation"
In this large, comprehensive paper we present detailed analysis of the host galaxies of the 23 "darkest" GRBs during the five-year period from 2005-2009. We provide redshifts of every object and using a custom SED fitting procedure show these hosts to be much more massive and luminous than "ordinary" GRB hosts. However, the GRB population overall still appears (even with this population included) to trend towards lower-mass, lower-metallicity galaxies than star-formation in the Universe overall, suggesting that the efficiency at which a galaxy forms a GRB progenitor depends on broader environmental conditions.
- Perley, Modjaz, Morgan et al. (2012): "The Luminous Infrared Host Galaxy of Short-duration GRB 100206A"
Short-duration GRBs are thought to be associated with old stellar population, but GRB 100206A occurred at the location of an extremely luminous, dusty, rapidly star-forming galaxy. In this paper we present detailed analysis of the host and discuss whether this most extreme of short GRB hosts may be indicative of an association of some events with recent star-formation.
- Perley, Morgan, Updike et al. (2011): "Monster in the Dark: The Ultraluminous GRB 080607 and its Dusty Environment"
The second most luminous GRB on record (at optical/UV wavelengths) occurred behind a dark molecular cloud at a redshift of z=3, offering a nearly perfect opportunity to study the dust properties of an event in the early universe. We show that the dust extinction curve is quite similar to local templates and place this GRB in the context of other events, like GRB 080319B.
- Perley, Bloom, Klein et al. (2010): "Evidence of Supernova-Synthesized Dust from the Afterglow of GRB 071025 at z=5"
The highest-redshift PAIRITEL-detected burst to date, dating to only 1.3 billion years after the Big Bang, was obscured by dust with an unusual extinction law indicative of silicate and other compounds formed by previous supernovae in that galaxy. By comparison, dust in the modern universe is thought to have been formed by red giant stars.
- Perley, Cenko, Bloom et al. (2009): "The Host Galaxies of Swift Dark Gamma-Ray Bursts: Observational Constraints on Highly Obscured and Very High-Redshift GRBs"
Here we examine a subsample of our host observations with uniform, deep early optical afterglow coverage from the P60 robotic telescope. Almost every "dark" event has a detectable host, ruling out the high redshift scenario as a predominant cause of dark bursts. We instead favor host-galaxy dust extinction (up to 5-10 magnitudes in some cases) as the predominant cause of dark bursts.
- Perley, Metzger, Granot et al. (2009): "GRB 080503: Implications of a Naked Short Gamma-Ray Burst Dominated by Extended Emission"
(ApJ 696:1871 2009)
This bright short gamma-ray burst showed one of the faintest afterglows on record, suggesting it had exploded in a near-vaccuum, in accordance with predictions of short gamma-ray bursts being ejected from their host galaxies. At the same time, the puzzling nature of its gamma-ray light curve poses theoretical difficulties for some of the leading models.
- Prochaska, Sheffer, Perley et al. (2009): "The First Positive Detection of Molecular Gas in a GRB Host Galaxy"
(ApJ 691:27 2009)
A phenomenal burst at a redshift of z=3 that fortuitously occurred while we were at Keck showed features that the community had been seeking for over a decade: molecular lines (in addition to hundreds of ionic lines). By combining the Keck spectrum with optical and infrared afterglow follow-up we were also able to constrain the dust properties and report a secure detection of the locally ubiquitous 2175-Angstrom dust feature.
- Bloom, Perley, Li et al. (2008): "Observations of the Naked-Eye GRB 080319B: Implications of Nature's Brightest Explosion"
(ApJ 691:723 2009)
GRB 080319B is the brightest and most optically luminous gamma-ray burst ever observed and has perhaps the best early data-set to date of any gamma-ray burst. We followed the burst starting from 1 minute and until many months after the burst, interpreting its unusual light curve and discussing implications for the observability of GRBs in the distant universe.
- Perley, Li, Chornock et al. (2008): "GRB 071003: Broadband Follow-up Observations of a Very Bright Gamma-Ray Burst in a Galactic Halo"
(ApJ 688:470 2008)
One of the brightest bursts that year, this event displayed several puzzling features including a dramatic late-time rebrightening and, most curiously, almost no sign of absorption from its host galaxy. No host galaxy was identified at the burst location. This burst either occurred in an extremely small galaxy or in a halo, perhaps in a tidal tail.
- Perley, Bloom, Butler et al. (2008): "The Troublesome Broadband Evolution of GRB 061126: Does a Gray Burst Imply Gray Dust?"
(ApJ 672:449 2007)
This extremely bright gamma-ray burst had among the best early broad-band coverage for any event, with simultaneous, highly precise measurements from the UV (2000 Angstroms) to IR (20000 Angstroms) plus X-ray follow-up. Surprisingly, relative to the X-ray the optical band appears strongly extinguished, but hardly reddened at all, suggesting the possible need for "gray" dust. This burst is probably the best example to date of this phenomenon.
Many additional publications are available via ADS below.
- All accepted journal publications
- ArXiv pre-prints
- All first-author proceedings and conference abstracts
- All GCN Circulars