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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

2706 results found.

  1. GRB 131202A: theoretical estimation of the redshift
  2. GRB 060614: theoretical derivation of the redshift and need for deeper search of the host galaxy
  3. GRB 131128A: Swift detection of a burst
  4. GRB 131122A: i-band observations from NOT
  5. IPN Triangulation of GRB 131118A
  6. GRB 130925A: HST imaging
  7. GRB 131108A: 1.23m CAHA optical candidate
  8. GRB 131108A: Swift detection of a possible X-ray afterglow
  9. GRB 131103A: Swift detection of a burst
  10. GRB 131024C: ICSP discovery of a burst in X-rays by balloon borne study
  11. IPN Triangulation of GRB 131028A (long/bright)
  12. Swift Trigger 575905/possible GRB 131026A: Swift-XRT observations
  13. Swift Trigger 575905: a possible GRB
  14. IPN triangulation of GRB 131011B (Swift Trigger 574266)
  15. IPN Triangulation of GRB 131014A
  16. GRB 131014A: RATIR Optical and NIR Observations
  17. GRB 131014A: NOT afterglow candidate
  18. GRB 131014A: Nanshan optical observations
  19. GRB 131014A: Swift detection of a possible X-ray afterglow
  20. Fermi403206457: continued P60 observations and fading behavior
  21. Fermi403206457: iPTF detection of a possible optical afterglow
  22. GRB 130925A: Possible signatures of binary nature in the afterglow - Request for observations
  23. GRB131004A: TNG Redshift confirmation
  24. GRB131004A: Magellan Redshift
  25. GRB 131004A: TNG optical afterglow confirmation
  26. GRB 130925A: continuing Swift/XRT monitoring
  27. Konus-Wind observation of GRB 130925A
  28. Observation of possible GRB/TDE 130925A by INTEGRAL/SPI-ACS: three activity episodes
  29. Fermi GBM detection of GRB 130925A and a possible precursor
  30. GRB 130925A: Swift-XRT refined Analysis
  31. GRB 130831A: Maidanak optical observations, possible emerging Supernova
  32. GRB 130913A detected in ground analysis of Swift-BAT data
  33. GRB 130912A: REM optical/NIR upper limits
  34. GRB 130907A: Early Tautenburg detections, red afterglow
  35. GRB 130907A: Skynet DSO-14/Yerkes-41 detections of a possible afterglow
  36. Swift follow-up results of the possible weak INTEGRAL GRB
  37. Swift follow-up of an INTEGRAL possible weak GRB
  38. Swift Trigger 569022: a possible GRB
  39. IPN triangulation of GRB 130828A
  40. IPN triangulation of GRB130821A
  41. GRB 130821A: Swift-XRT observation
  42. Refined IPN Triangulation of GRB 130812B
  43. GRB 130806A: Swift detection of a burst
  44. GRB130803A: GROND detection of possible host
  45. GRB 130722A: Swift/UVOT Detection
  46. GRB 130626A: Retraction of possible X-ray afterglow
  47. GMRT radio detection of GRB 130702A
  48. GRB 130702A: Maidanak optical observations
  49. GRB 130702A (= Fermi 394416326): correction of the GCN #14988 title
  50. GRB 130702A: NOT spectroscopy and redshift of the nearby bright galaxy
  51. Fermi GRB 130702A: Swift XRT and UVOT observations
  52. GRB 130702A / Fermi394416326 : Fermi-LAT detection of a burst
  53. Fermi394416326: FTN detection
  54. Fermi394416326: iPTF detection of a possible optical afterglow
  55. GRB 130627B: Possible Swift-XRT afterglow detection
  56. GRB 130626A: Swift-XRT possible detection and UVOT upper limits
  57. GRB 130603B: Analogy with GRB 090510A and possible connection with a supernova
  58. GRB 130603B: Detection of possible afterglow/kilonova in HST observations
  59. GMRT radio observation of GRB 130603B
  60. GRB 130606A: Errata Ks magnutide in GCN 14792
  61. Swift/UVOT observations of GRB130603A
  62. Swift Trigger 556533 is probably not an astrophysical event
  63. GRB 130518A: Swift XRT and UVOT possible afterglow
  64. GRB 130427A: Continued RATIR Optical and NIR Observations - Photometric Evidence for a New Component
  65. GRB 130427A: Skynet detections of a possible supernova
  66. GRB 130514B Swift-BAT observations
  67. GRB 130515A: GROND Observations
  68. GRB 130427A: Tautenburg 2nd epoch: No break, no clear SN
  69. GRB 130427A: host galaxy observations
  70. GRB 130505B: Swift Candidate Afterglow
  71. Refined IPN Triangulation of GRB 130502B
  72. Konus-Wind observation of GRB 130504C
  73. GRB 130504C: Swift-XRT observations
  74. GRB 130502B: possible TNG counterpart
  75. Trigger 555096: Swift detection of a possible burst
  76. GRB 130427A: Pan-STARRS 1 optical observations
  77. GRB 130427A: Predictions about the occurrence of a supernova
  78. GRB 130427A: GMRT radio detection
  79. GRB 130427A: photo-z of possible SDSS host galaxy
  80. GRB 130427A: high energy gamma-ray detection by AGILE
  81. GRB 130427A: Nishi-Harima NIR Observations
  82. GRB 130427A: P60 early nondetection
  83. Trigger 554491: Swift detection of a spike possibly from Sgr A*
  84. GRB 130327B: Swift/XRT source is not the afterglow
  85. Trigger 553930: Swift detection of a possible flare from HR 5110
  86. GRB 130408A, Swift-BAT refined analysis
  87. GRB 130306A: Confirmation of the X-ray Afterglow
  88. Swift Trigger 552142: a possible GRB
  89. GRB 130327A: PAIRITEL NIR Afterglow Candidate
  90. GRB 130315A: Swift detection of a burst
  91. GRB 130313A: Swift-XRT detection of a possible X-ray afterglow
  92. Swift XRT observations of GRB 130310A
  93. GRB 130306A: Swift Detection of a Possible Afterglow
  94. GBM trigger 383712005 (GRB 130228A?) : Possible high-energy photon emission in Fermi/LAT data
  95. GRB 130216A: possible radio counterpart is steady field source
  96. GRB 130216A: possible early detection at 15 GHz
  97. Swift/BAT trigger 547142 is new source Swift J1753.7-2544
  98. Swift Trigger 544381 is unlikely to be a GRB
  99. GRB 121209A: Early CARMA Observations
  100. GRB 121211A: Keck/LRIS redshift

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