GRB 070714B
{{Short description|Highly luminous gamma ray burst from a neutron star merger}}
{{Infobox astronomical event
| ra = {{RA|03|51|22.29}}
| dec = {{DEC|+28|17|52.2}}
| energy = 1.2{{e|51}} ergs
|name=GRB 070714B|caption=Illustration of GRB 070714B|image=GRB 070714B 1.jpg}}
GRB 070714B was a gamma-ray burst (GRB) that was detected on 14 July 2007 at 04:59 UTC. A gamma-ray burst is a highly luminous flash associated with an explosion in a distant galaxy and producing gamma rays, the most energetic form of electromagnetic radiation, and often followed by a longer-lived "afterglow" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, and radio).
At a total duration of only 3 seconds, GRB 070714B was classified as a short burst, a subclass of GRBs which is believed to be caused by the merger of two neutron stars. GRB 070714B had a redshift of z = 0.92, corresponding to a distance of about 7.4 billion light years, making it the most distant short burst detected as of 2007.
Observations
GRB 070714B was detected by the Swift Gamma-Ray Burst Mission satellite on 14 July 2007 at 04:59 UTC. The burst lasted only 3 seconds and reached its peak intensity 0.2 seconds after the initial detection.{{cite journal | title = GRB 070714: Swift detection of a bright burst, possibly short | author = Barthelmy, Scott | journal = GCN Circulars | volume = 6620 | date = 14 July 2007 | url =http://gcn.gsfc.nasa.gov/gcn3/6620.gcn3 |page=1| bibcode =2007GCN..6620....1R }} The optical afterglow was detected by the Liverpool Telescope{{cite journal | title = GRB 070714 : Liverpool Telescope optical counterpart? | author = Melandri, Andrea | journal = GCN Circulars | volume = 6621 | date = 14 July 2007 | url = http://gcn.gsfc.nasa.gov/gcn3/6621.gcn3 |page=1| bibcode = 2007GCN..6621....1M }} and the William Herschel Telescope.{{cite journal | title = GRB 070714B: confirmation of optical afterglow | author = Levan, Andrew | journal = GCN Circulars | volume = 6630 | date = 14 July 2007 | url = http://gcn.gsfc.nasa.gov/gcn3/6630.gcn3 |page=1}}
Distance record
Spectroscopy of the optical afterglow and the burst's host galaxy revealed a single emission line of oxygen at a redshift of z = 0.92.{{cite journal | title = GRB 070714B—Discovery of the Highest Spectroscopically Confirmed Short Burst Redshift | author = Graham, J. F. | display-authors = etal | journal = The Astrophysical Journal | volume = 698 | issue = 2 | pages = 1620–1629 | doi = 10.1088/0004-637X/698/2/1620 | date = 3 June 2009 | bibcode=2009ApJ...698.1620G|arxiv = 0808.2610 }} This corresponds to a distance of 7.4 billion light years, making it the oldest and most distant short burst ever detected.{{cite web | url = http://www.nasa.gov/centers/goddard/news/topstory/2007/gemini_explosion.html | title = NASA and Gemini Probe Mysterious Distant Explosion | date = 8 January 2008 | accessdate = 14 July 2010 | author = Naeye, Robert | publisher = NASA Goddard Space Flight Center }} The previous record holder had been GRB 051221A at a redshift of z = 0.546.{{cite journal | title = The Afterglow, Energetics, and Host Galaxy of the Short-Hard Gamma-Ray Burst 051221a | author = Soderberg, A. M. |author-link=Alicia M. Soderberg | display-authors = etal | journal = The Astrophysical Journal | date = 10 October 2006 | volume = 650 | pages = 261–271 |arxiv = astro-ph/0601455 |bibcode = 2006ApJ...650..261S |doi = 10.1086/506429 | issue=1}} At a redshift of z = 0.92, the total energy released by GRB 070714B (assuming isotropic emission) was approximately 1.2{{e|51}} ergs, which is several orders of magnitude higher than short-duration bursts with a redshift less than z = 0.5, but still significantly smaller than typical long-duration bursts.{{cite journal | title = GRBs 070429B and 070714B: The High End of the Short-Duration Gamma-Ray Burst Redshift Distribution | author = Cenko, S. Bradley | display-authors = etal | journal = The Astrophysical Journal | date = 7 February 2008 | arxiv = 0802.0874 |bibcode = 2008arXiv0802.0874C }}