Editing Gamma-ray burst (section)

=== Ultra-long gamma-ray bursts ===
ulGRB are defined as GRB lasting more than 10,000 seconds, covering the upper range to the limit of the GRB duration distribution. They have been proposed to form a separate class, caused by the collapse of a [[blue supergiant|blue supergiant star]],<ref>{{cite journal |bibcode=2013ApJ...766...30G |doi=10.1088/0004-637X/766/1/30 |title=The Ultra-Long Gamma-Ray Burst 111209A: The Collapse of a Blue Supergiant? |journal=The Astrophysical Journal |volume=766 |issue=1 |page=30 |date=2013 |last1=Gendre |first1=B. |last2=Stratta |first2=G. |last3=Atteia |first3=J. L. |last4=Basa |first4=S. |last5=Boër |first5=M. |last6=Coward |first6=D. M. |last7=Cutini |first7=S. |last8=d'Elia |first8=V. |last9=Howell |first9=E. J |last10=Klotz |first10=A. |last11=Piro |first11=L. |s2cid=118618287 |arxiv = 1212.2392 }}</ref> a [[tidal disruption event]]<ref name="Greiner Mazzali Kann Krühler pp. 189–192">{{cite journal | last1=Greiner | first1=Jochen | last2=Mazzali | first2=Paolo A. | last3=Kann | first3=D. Alexander | last4=Krühler | first4=Thomas | last5=Pian | first5=Elena | last6=Prentice | first6=Simon | last7=Olivares E. | first7=Felipe | last8=Rossi | first8=Andrea | last9=Klose | first9=Sylvio | last10=Taubenberger | first10=Stefan | last11=Knust | first11=Fabian | last12=Afonso | first12=Paulo M. J. | last13=Ashall | first13=Chris | last14=Bolmer | first14=Jan | last15=Delvaux | first15=Corentin | last16=Diehl | first16=Roland | last17=Elliott | first17=Jonathan | last18=Filgas | first18=Robert | last19=Fynbo | first19=Johan P. U. | last20=Graham | first20=John F. | last21=Guelbenzu | first21=Ana Nicuesa | last22=Kobayashi | first22=Shiho | last23=Leloudas | first23=Giorgos | last24=Savaglio | first24=Sandra | last25=Schady | first25=Patricia |author25-link= Patricia Schady | last26=Schmidl | first26=Sebastian | last27=Schweyer | first27=Tassilo | last28=Sudilovsky | first28=Vladimir | last29=Tanga | first29=Mohit | last30=Updike | first30=Adria C. | last31=van Eerten | first31=Hendrik | last32=Varela | first32=Karla | s2cid=4464998 | title=A very luminous magnetar-powered supernova associated with an ultra-long γ-ray burst | journal=Nature | volume=523 | issue=7559 | date=2015-07-08  | doi=10.1038/nature14579 | pmid=26156372 | display-authors=29 | pages=189–192|arxiv = 1509.03279 |bibcode = 2015Natur.523..189G }}</ref><ref name="Levan Tanvir Starling Wiersema">{{cite journal | last1=Levan | first1=A. J. | last2=Tanvir | first2=N. R. | last3=Starling | first3=R. L. C. | last4=Wiersema | first4=K. | last5=Page | first5=K. L. | last6=Perley | first6=D. A. | last7=Schulze | first7=S. | last8=Wynn | first8=G. A. | last9=Chornock | first9=R. | last10=Hjorth | first10=J. | last11=Cenko | first11=S. B. | last12=Fruchter | first12=A. S. | last13=O'Brien | first13=P. T. | last14=Brown | first14=G. C. | last15=Tunnicliffe | first15=R. L. | last16=Malesani | first16=D. | last17=Jakobsson | first17=P. | last18=Watson | first18=D. | last19=Berger | first19=E. | last20=Bersier | first20=D. | last21=Cobb | first21=B. E. | last22=Covino | first22=S. | last23=Cucchiara | first23=A. | last24=de Ugarte Postigo | first24=A. | last25=Fox | first25=D. B. | last26=Gal-Yam | first26=A. | last27=Goldoni | first27=P. | last28=Gorosabel | first28=J. | last29=Kaper | first29=L. | last30=Krühler | first30=T. | last31=Karjalainen | first31=R. | last32=Osborne | first32=J. P. | last33=Pian | first33=E. | last34=Sánchez-Ramírez | first34=R. | last35=Schmidt | first35=B. | last36=Skillen | first36=I. | last37=Tagliaferri | first37=G. | last38=Thöne | first38=C. | last39=Vaduvescu | first39=O. | last40=Wijers | first40=R. A. M. J. | last41=Zauderer | first41=B. A. | title=A new population of ultra-long duration gamma-ray bursts | journal=The Astrophysical Journal | volume=781 | issue=1 | year=2014 |display-authors=29 | arxiv=1302.2352 | doi=10.1088/0004-637x/781/1/13 | page=13 | bibcode=2014ApJ...781...13L| s2cid=24657235 }}</ref> or a new-born [[magnetar]].<ref name="Greiner Mazzali Kann Krühler pp. 189–192" /><ref name="Ioka Hotokezaka Piran p=110">{{cite journal | last1=Ioka | first1=Kunihito | last2=Hotokezaka | first2=Kenta | last3=Piran | first3=Tsvi | s2cid=118629696 | title=Are Ultra-Long Gamma-Ray Bursts Caused by Blue Supergiant Collapsars, Newborn Magnetars, or White Dwarf Tidal Disruption Events? | journal=The Astrophysical Journal | volume=833 | issue=1 | date=2016-12-12  | doi=10.3847/1538-4357/833/1/110 | page=110|arxiv = 1608.02938 |bibcode = 2016ApJ...833..110I | doi-access=free }}</ref> Only a small number have been identified to date, their primary characteristic being their gamma ray emission duration. The most studied ultra-long events include [[GRB 101225A]] and [[GRB 111209A]].<ref name="Levan Tanvir Starling Wiersema"/><ref>{{cite journal |arxiv=1310.4944 |last1=Boer |first1=Michel |title=Are Ultra-long Gamma-Ray Bursts different? |journal=The Astrophysical Journal |volume=800 |issue=1 |pages=16 |last2=Gendre |first2=Bruce |last3=Stratta |first3=Giulia |s2cid=118655406 |doi=10.1088/0004-637X/800/1/16 |date=2013 |bibcode = 2015ApJ...800...16B }}</ref><ref>{{cite journal |bibcode=2013ApJ...778...54V |doi=10.1088/0004-637X/778/1/54 |title=Grb 091024A and the Nature of Ultra-Long Gamma-Ray Bursts |journal=The Astrophysical Journal |volume=778 |issue=1 |page=54 |date=2013 |last1=Virgili |first1=F. J. |last2=Mundell |first2=C. G. |last3=Pal'Shin |first3=V. |last4=Guidorzi |first4=C. |last5=Margutti |first5=R. |last6=Melandri |first6=A. |last7=Harrison |first7=R. |last8=Kobayashi |first8=S. |last9=Chornock |first9=R. |last10=Henden |first10=A. |last11=Updike |first11=A. C. |last12=Cenko |first12=S. B. |last13=Tanvir |first13=N. R. |last14=Steele |first14=I. A. |last15=Cucchiara |first15=A. |last16=Gomboc |first16=A. |last17=Levan |first17=A. |last18=Cano |first18=Z. |last19=Mottram |first19=C. J. |last20=Clay |first20=N. R. |last21=Bersier |first21=D. |last22=Kopač |first22=D. |last23=Japelj |first23=J. |last24=Filippenko |first24=A. V. |last25=Li |first25=W. |last26=Svinkin |first26=D. |last27=Golenetskii |first27=S. |last28=Hartmann |first28=D. H. |last29=Milne |first29=P. A. |last30=Williams |first30=G. |s2cid=119023750 |display-authors=29 |arxiv = 1310.0313 }}</ref> The low detection rate may be a result of low sensitivity of current detectors to long-duration events, rather than a reflection of their true frequency.<ref name="Levan Tanvir Starling Wiersema"/> A 2013 study,<ref>{{cite journal |arxiv=1310.2540 |last1=Zhang |first1=Bin-Bin |title=How Long does a Burst Burst? |journal=The Astrophysical Journal |volume=787 |issue=1 |page=66 |last2=Zhang |first2=Bing |last3=Murase |first3=Kohta |last4=Connaughton |first4=Valerie |last5= Briggs |first5=Michael S. |s2cid=56273013 |year=2014 |doi=10.1088/0004-637X/787/1/66 |bibcode = 2014ApJ...787...66Z }}</ref> on the other hand, shows that the existing evidence for a separate ultra-long GRB population with a new type of progenitor is inconclusive, and further multi-wavelength observations are needed to draw a firmer conclusion.