skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Fermi LAT Stacking Analysis of Swift Localized GRBs

Abstract

In this paper, we perform a comprehensive stacking analysis of data collected by the Fermi Large Area Telescope (LAT) of γ-ray bursts (GRBs) localized by the Swift spacecraft, which were not detected by the LAT but which fell within the instrument's field of view at the time of trigger. We examine a total of 79 GRBs by comparing the observed counts over a range of time intervals to that expected from designated background orbits, as well as by using a joint likelihood technique to model the expected distribution of stacked counts. We find strong evidence for subthreshold emission at MeV to GeV energies using both techniques. This observed excess is detected during intervals that include and exceed the durations typically characterizing the prompt emission observed at keV energies and lasts at least 2700 s after the co-aligned burst trigger. By utilizing a novel cumulative likelihood analysis, we find that although a burst's prompt γ-ray and afterglow X-ray flux both correlate with the strength of the subthreshold emission, the X-ray afterglow flux measured by Swift's X-ray Telescope at 11 hr post trigger correlates far more significantly. Overall, the extended nature of the subthreshold emission and its connection to the burst's afterglowmore » brightness lend further support to the external forward shock origin of the late-time emission detected by the LAT. Finally, these results suggest that the extended high-energy emission observed by the LAT may be a relatively common feature but remains undetected in a majority of bursts owing to instrumental threshold effects.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE; National Aeronautics and Space Administration (NASA); Japan Aerospace Exploration Agency (JAXA); K.A. Wallenberg Foundation; Swedish Research Council (SRC)
Contributing Org.:
Fermi LAT Collaboration
OSTI Identifier:
1355697
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Volume: 822; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; gamma-ray burst; gamma rays; data analysis methods; X-ray bursts

Citation Formats

Ackermann, M., Ajello, M., Anderson, B., Atwood, W. B., Axelsson, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Bhat, P. N., Bissaldi, E., Bonino, R., Bottacini, E., Brandt, T. J., Bregeon, J., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caragiulo, M., Caraveo, P. A., Cecchi, C., Charles, E., Chekhtman, A., Chiang, J., Chiaro, G., Ciprini, S., Claus, R., Cohen-Tanugi, J., Conrad, J., Cutini, S., D’Ammando, F., de Angelis, A., de Palma, F., Desiante, R., Di Venere, L., Drell, P. S., Favuzzi, C., Focke, W. B., Franckowiak, A., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Giglietto, N., Giordano, F., Giroletti, M., Godfrey, G., Grenier, I. A., Grove, J. E., Guiriec, S., Hewitt, J. W., Hill, A. B., Horan, D., Jóhannesson, G., Kocevski, D., Kouveliotou, C., Kuss, M., Larsson, S., Li, J., Li, L., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Mayer, M., Mazziotta, M. N., McEnery, J. E., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Murgia, S., Nemmen, R., Nuss, E., Ohno, M., Ohsugi, T., Omodei, N., Orienti, M., Orlando, E., Paneque, D., Perkins, J. S., Pesce-Rollins, M., Piron, F., Pivato, G., Porter, T. A., Racusin, J. L., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Schaal, M., Schulz, A., Sgrò, C., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Takahashi, H., Thayer, J. B., Tibaldo, L., Tinivella, M., Torres, D. F., Tosti, G., Troja, E., Vianello, G., Kienlin, A. von, Werner, M., and Wood, K. S. Fermi LAT Stacking Analysis of Swift Localized GRBs. United States: N. p., 2016. Web. doi:10.3847/0004-637X/822/2/68.
Ackermann, M., Ajello, M., Anderson, B., Atwood, W. B., Axelsson, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Bhat, P. N., Bissaldi, E., Bonino, R., Bottacini, E., Brandt, T. J., Bregeon, J., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caragiulo, M., Caraveo, P. A., Cecchi, C., Charles, E., Chekhtman, A., Chiang, J., Chiaro, G., Ciprini, S., Claus, R., Cohen-Tanugi, J., Conrad, J., Cutini, S., D’Ammando, F., de Angelis, A., de Palma, F., Desiante, R., Di Venere, L., Drell, P. S., Favuzzi, C., Focke, W. B., Franckowiak, A., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Giglietto, N., Giordano, F., Giroletti, M., Godfrey, G., Grenier, I. A., Grove, J. E., Guiriec, S., Hewitt, J. W., Hill, A. B., Horan, D., Jóhannesson, G., Kocevski, D., Kouveliotou, C., Kuss, M., Larsson, S., Li, J., Li, L., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Mayer, M., Mazziotta, M. N., McEnery, J. E., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Murgia, S., Nemmen, R., Nuss, E., Ohno, M., Ohsugi, T., Omodei, N., Orienti, M., Orlando, E., Paneque, D., Perkins, J. S., Pesce-Rollins, M., Piron, F., Pivato, G., Porter, T. A., Racusin, J. L., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Schaal, M., Schulz, A., Sgrò, C., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Takahashi, H., Thayer, J. B., Tibaldo, L., Tinivella, M., Torres, D. F., Tosti, G., Troja, E., Vianello, G., Kienlin, A. von, Werner, M., & Wood, K. S. Fermi LAT Stacking Analysis of Swift Localized GRBs. United States. https://doi.org/10.3847/0004-637X/822/2/68
Ackermann, M., Ajello, M., Anderson, B., Atwood, W. B., Axelsson, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Bhat, P. N., Bissaldi, E., Bonino, R., Bottacini, E., Brandt, T. J., Bregeon, J., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caragiulo, M., Caraveo, P. A., Cecchi, C., Charles, E., Chekhtman, A., Chiang, J., Chiaro, G., Ciprini, S., Claus, R., Cohen-Tanugi, J., Conrad, J., Cutini, S., D’Ammando, F., de Angelis, A., de Palma, F., Desiante, R., Di Venere, L., Drell, P. S., Favuzzi, C., Focke, W. B., Franckowiak, A., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Giglietto, N., Giordano, F., Giroletti, M., Godfrey, G., Grenier, I. A., Grove, J. E., Guiriec, S., Hewitt, J. W., Hill, A. B., Horan, D., Jóhannesson, G., Kocevski, D., Kouveliotou, C., Kuss, M., Larsson, S., Li, J., Li, L., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Mayer, M., Mazziotta, M. N., McEnery, J. E., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Murgia, S., Nemmen, R., Nuss, E., Ohno, M., Ohsugi, T., Omodei, N., Orienti, M., Orlando, E., Paneque, D., Perkins, J. S., Pesce-Rollins, M., Piron, F., Pivato, G., Porter, T. A., Racusin, J. L., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Schaal, M., Schulz, A., Sgrò, C., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Takahashi, H., Thayer, J. B., Tibaldo, L., Tinivella, M., Torres, D. F., Tosti, G., Troja, E., Vianello, G., Kienlin, A. von, Werner, M., and Wood, K. S. 2016. "Fermi LAT Stacking Analysis of Swift Localized GRBs". United States. https://doi.org/10.3847/0004-637X/822/2/68. https://www.osti.gov/servlets/purl/1355697.
@article{osti_1355697,
title = {Fermi LAT Stacking Analysis of Swift Localized GRBs},
author = {Ackermann, M. and Ajello, M. and Anderson, B. and Atwood, W. B. and Axelsson, M. and Baldini, L. and Barbiellini, G. and Bastieri, D. and Bellazzini, R. and Bhat, P. N. and Bissaldi, E. and Bonino, R. and Bottacini, E. and Brandt, T. J. and Bregeon, J. and Bruel, P. and Buehler, R. and Buson, S. and Caliandro, G. A. and Cameron, R. A. and Caragiulo, M. and Caraveo, P. A. and Cecchi, C. and Charles, E. and Chekhtman, A. and Chiang, J. and Chiaro, G. and Ciprini, S. and Claus, R. and Cohen-Tanugi, J. and Conrad, J. and Cutini, S. and D’Ammando, F. and de Angelis, A. and de Palma, F. and Desiante, R. and Di Venere, L. and Drell, P. S. and Favuzzi, C. and Focke, W. B. and Franckowiak, A. and Funk, S. and Fusco, P. and Gargano, F. and Gasparrini, D. and Gehrels, N. and Giglietto, N. and Giordano, F. and Giroletti, M. and Godfrey, G. and Grenier, I. A. and Grove, J. E. and Guiriec, S. and Hewitt, J. W. and Hill, A. B. and Horan, D. and Jóhannesson, G. and Kocevski, D. and Kouveliotou, C. and Kuss, M. and Larsson, S. and Li, J. and Li, L. and Longo, F. and Loparco, F. and Lovellette, M. N. and Lubrano, P. and Mayer, M. and Mazziotta, M. N. and McEnery, J. E. and Michelson, P. F. and Mizuno, T. and Monzani, M. E. and Morselli, A. and Murgia, S. and Nemmen, R. and Nuss, E. and Ohno, M. and Ohsugi, T. and Omodei, N. and Orienti, M. and Orlando, E. and Paneque, D. and Perkins, J. S. and Pesce-Rollins, M. and Piron, F. and Pivato, G. and Porter, T. A. and Racusin, J. L. and Rainò, S. and Rando, R. and Razzano, M. and Reimer, A. and Reimer, O. and Schaal, M. and Schulz, A. and Sgrò, C. and Siskind, E. J. and Spada, F. and Spandre, G. and Spinelli, P. and Takahashi, H. and Thayer, J. B. and Tibaldo, L. and Tinivella, M. and Torres, D. F. and Tosti, G. and Troja, E. and Vianello, G. and Kienlin, A. von and Werner, M. and Wood, K. S.},
abstractNote = {In this paper, we perform a comprehensive stacking analysis of data collected by the Fermi Large Area Telescope (LAT) of γ-ray bursts (GRBs) localized by the Swift spacecraft, which were not detected by the LAT but which fell within the instrument's field of view at the time of trigger. We examine a total of 79 GRBs by comparing the observed counts over a range of time intervals to that expected from designated background orbits, as well as by using a joint likelihood technique to model the expected distribution of stacked counts. We find strong evidence for subthreshold emission at MeV to GeV energies using both techniques. This observed excess is detected during intervals that include and exceed the durations typically characterizing the prompt emission observed at keV energies and lasts at least 2700 s after the co-aligned burst trigger. By utilizing a novel cumulative likelihood analysis, we find that although a burst's prompt γ-ray and afterglow X-ray flux both correlate with the strength of the subthreshold emission, the X-ray afterglow flux measured by Swift's X-ray Telescope at 11 hr post trigger correlates far more significantly. Overall, the extended nature of the subthreshold emission and its connection to the burst's afterglow brightness lend further support to the external forward shock origin of the late-time emission detected by the LAT. Finally, these results suggest that the extended high-energy emission observed by the LAT may be a relatively common feature but remains undetected in a majority of bursts owing to instrumental threshold effects.},
doi = {10.3847/0004-637X/822/2/68},
url = {https://www.osti.gov/biblio/1355697}, journal = {The Astrophysical Journal (Online)},
issn = {1538-4357},
number = 2,
volume = 822,
place = {United States},
year = {Thu May 05 00:00:00 EDT 2016},
month = {Thu May 05 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 1 work
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope
journal, December 2011


THE FERMI LARGE AREA TELESCOPE ON ORBIT: EVENT CLASSIFICATION, INSTRUMENT RESPONSE FUNCTIONS, AND CALIBRATION
journal, October 2012


MULTIWAVELENGTH OBSERVATIONS OF GRB 110731A: GeV EMISSION FROM ONSET TO AFTERGLOW
journal, January 2013


THE FIRST FERMI -LAT GAMMA-RAY BURST CATALOG
journal, October 2013


Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A
journal, November 2013


SEARCH FOR DARK MATTER SATELLITES USING FERMI -LAT
journal, February 2012


THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION
journal, May 2009


NEW FERMI -LAT EVENT RECONSTRUCTION REVEALS MORE HIGH-ENERGY GAMMA RAYS FROM GAMMA-RAY BURSTS
journal, August 2013


The Burst Alert Telescope (BAT) on the SWIFT Midex Mission
journal, October 2005


SWIFT AND FERMI OBSERVATIONS OF THE EARLY AFTERGLOW OF THE SHORT GAMMA-RAY BURST 090510
journal, January 2010


THE HEASARC Swift GAMMA-RAY BURST ARCHIVE: THE PIPELINE AND THE CATALOG
journal, October 2012


Methods and results of an automatic analysis of a complete sample of Swift -XRT observations of GRBs
journal, August 2009


On the generation of high-energy photons detected by the Fermi Satellite from gamma-ray bursts
journal, November 2009


The average GeV-band emission from gamma-ray bursts
journal, February 2013


Analysis methods for results in gamma-ray astronomy
journal, September 1983


THE FERMI GAMMA-RAY BURST MONITOR
journal, August 2009


Evidence for a Canonical Gamma‐Ray Burst Afterglow Light Curve in the Swift XRT Data
journal, May 2006


JET BREAKS AND ENERGETICS OF Swift GAMMA-RAY BURST X-RAY AFTERGLOWS
journal, May 2009


A Leptonic–Hadronic Model for the Afterglow of Gamma-Ray Burst 090510
journal, November 2010


The Swift Ultra-Violet/Optical Telescope
journal, October 2005


Works referencing / citing this record:

Unbiased Long-Term Monitoring at TeV Energies
text, January 2019


The High Energy View of FR0 Radio Galaxies
journal, September 2019


Unbiased Long-Term Monitoring at TeV Energies
journal, April 2019


The High Energy View of FR0 Radio Galaxies
preprint, January 2019