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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"

8293 results found.

  1. GRB 030131: marginal optical detection
  2. GRB030131: Candidate Optical Afterglow
  3. GRB 030131, optical observations
  4. GRB030131: Kiso optical limit for corrected position
  5. GRB030131: Optical limits for corrected position
  6. GRB 030131: afterglow candidate
  7. GRB 020819: afterglow candidate
  8. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  9. GRB030115 submm upper limit
  10. GRB 030115: Further IR observations with IRSF/SIRIUS
  11. Publicizing GRB Discoveries - A Message from NASA HQ
  12. GRB 030115: Radio detection of IR candidate
  13. GRB 030115: IR observations with IRSF/SIRIUS
  14. GRB030115: R-band counterpart of IR candidate
  15. GRB030115, afterglow candidate
  16. GRB 021211: R-band observations at late-time
  17. GRB 030115, no optical candidate
  18. GRB 030115, optical candidate
  19. GRB 021211: Probable Host and Underlying Supernova
  20. Probable GRB in INTEGRAL SPI-ACS
  21. GRB 021112: Evidence for Another Dark Optical Afterglow
  22. XRF 020903 : HST observations
  23. GRB021204: Kiso Observations
  24. GRB 021201 (short/hard), NOT observations
  25. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  26. HETE 2493: Optical observations
  27. HETE 2493: Optical candidate
  28. IPN detection of renewed activity from SGR1806-20
  29. IPN detection of continued SGR1900+14 activity
  30. IPN confirmation of the reactivation of SGR1900+14
  31. IPN detection of possible reactivation of SGR1900+14
  32. GRB 021112: Afterglow or Variable Star?
  33. GRB 021112, Radio Observations
  34. GRB 021112: Variable Source in R-band search
  35. GRB 021113: Optical observations
  36. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  37. SGR1900+14 activity, November 2-4, 2002
  38. GRB021104: Candidate present in DSS
  39. GRB 021004: optical spectroscopy
  40. GRB021004: restart of optical decay
  41. GRB021004, Optical Observations
  42. GRB 021004: radio observations
  43. GRB 021004: Kyoto observation
  44. GRB021004: Optical Afterglow
  45. XRF 020903: Supernova
  46. XRF 020903: Optical observations
  47. Second epoch K band imaging of GRB 020819
  48. GRB 020813 : HST observations
  49. Confirming no variability for GRB02081
  50. GRB020819 : Optical observations at KISO
  51. GRB 020819 : OT candidate - confirmation of non variability
  52. GRB 020819: Optical observations
  53. K band observation of GRB 020819
  54. HETE 2275: Optical observations
  55. GRB020813: Fading X-ray Afterglow Observed with Chandra
  56. GRB020812: optical observations
  57. GRB020813(=H2262): Revised Localization with HETE SXC
  58. GRB 020813, radio detection
  59. GRB 020812 : optical afterglow candidate
  60. GRB020812: optical observations
  61. GRB020813, optical observations
  62. GRB020812: possible afterglow candidate
  63. GRB020812: possible afterglow candidate
  64. GRB020813, astrometric position
  65. GRB020813: Fading of Candidate OT
  66. GRB020813: Candidate Optical Afterglow
  67. GRB020801: Candidate OT present in DSS
  68. GRB020801, optical afterglow candidate
  69. GRB 020410: Discovery of Probable OT by HST
  70. GRB 020705: Optical observations
  71. GRB 020625: Optical observations
  72. GRB 020531: optical photometry of Chandra sources
  73. HETE #2081: Optical observations
  74. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  75. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  76. AXP 1E2259+586: quasi-simultaneous optical observation
  77. AXP 1E2259+586 optical observations
  78. SGR-like Bursts from the AXP 1E 2259+586
  79. GRB 020531/Candidate Redshift
  80. GRB020531: Detection of Candidate Host Galaxy
  81. GRB 020603: Optical observations
  82. GRB 020531 optical observations with TAROT
  83. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  84. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  85. XRF 020427
  86. GRB020331: Third Epoch and Revised Second Epoch Optical
  87. GRB 020418: Optical observations
  88. GRB 020418: Optical observations
  89. GRB020410: BeppoSAX NFI observations refined analysis
  90. GRB 020409: Optical observations
  91. GRB020406(?), optical observations
  92. GRB020410, optical observations
  93. X-ray afterglow of GRB020321
  94. GRB020331: Confirmation of Afterglow Candidate with Magellan
  95. GRB 020321: Candidate X-ray Counterparts
  96. ASM GRB candidate 020406 refined error box
  97. GRB020331: Optical Observations of Afterglow Candidate
  98. GRB020405: OT observations
  99. GRB 020331: Candidate Optical Afterglow
  100. GRB 020405: Decay index

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