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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"

14250 results found.

  1. SGR1806-20: A Second, Intense Burst Localized by HETE
  2. SGR1806-20: Localization by HETE
  3. GRB000301C: Late-time HST/STIS observation
  4. GRB010518: a faint BeppoSAX detection
  5. GRB000418: HST/STIS Second-epoch Observations
  6. SGR 1900+14: No evidence of extended X-ray emission
  7. SGR 1900+14: Detection of extended X-ray emission
  8. GRB 010222: High-Resolution Keck Spectroscopy
  9. GRB 010214, I-band data
  10. GRB 010222 Kyoto optical observation
  11. GRB010214 follow-up from Hanle
  12. GRB010222: Sub-millimeter detection
  13. GRB010222: Optical Observations
  14. GRB010222: possible optical counterpart
  15. GRB010220, Radio and Optical Observations
  16. GRB010213 Optical Observation
  17. GRB010213, Radio Observations
  18. GRB010214 Optical Observation
  19. IPN Status Report
  20. HETE Status
  21. GRB010126 opt. obs.
  22. GRB010126: CONCAM crude optical limits during GRB
  23. GRB010126 optical observations
  24. Optical Observations of GRB 001018 at Keck
  25. GRB 001212 Optical Observation
  26. Confirmation of IPN position for GRB001204
  27. WSRT 4.8 GHz observations of GRB001109
  28. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  29. GRB001007: Optical observations
  30. GRB000926 - Amateur Optical Observations
  31. CONCAM null result on GRB001005
  32. CONCAM crude optical limits before and after GRB000926
  33. GRB 990510: Possible detection of a host galaxy
  34. GRB 000630: Detection of the Optical Afterglow
  35. GRB000620: BeppoSAX WFC and GRBM detection
  36. GRB000615, R-band photometry
  37. GRB980425, HST/STIS observations of the host galaxy
  38. GRB000604 optical non-detection
  39. GRB000604, optical observations
  40. GRB 000418: Detection of the Host Galaxy
  41. X-ray Afterglow of GRB 000529
  42. Possible GRB-related phenomenon
  43. GRB000424, optical observations
  44. GRB000418, Radio detection
  45. GRB000418, K'-band photometry
  46. GRB 000418, Optical Observation
  47. GRB000424, optical observations
  48. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  49. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  50. GRB 000301C: A Precise Redshift Determination
  51. GRB 000301C: HST/STIS CCD Imaging of the field
  52. GRB000301C - Host galaxy not detected in R (?)
  53. GRB000301C 250 GHz detection
  54. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  55. GRB000214: BeppoSAX GRBM and WFC Detection
  56. Optical observations of the Chandra X-ray source for GRB000210
  57. GRB000210: possible afterglow detection with BeppoSAX NFI
  58. GRB000210: BeppoSAX GRBM and WFC Detection
  59. GRB 000131 Optical Observations
  60. GRB000126, optical observations
  61. Second RXTE Observation of GRB 000115
  62. GRB 991216 VLBA Observations
  63. GRB 991216: Detection of the Host and/or Absorber Galaxy
  64. GRB 991216 RXTE ASM Observations
  65. GRB 991216 Optical spectroscopy/imaging
  66. GRB 991208 Infrared Detection
  67. GRB 991216--Summary of RXTE Observations
  68. GRB991216 Optical Observations
  69. GRB991208 - millimeter detection
  70. GRB 991208 - OVRO detection
  71. GRB 991208 optical observations
  72. GRB991106: BeppoSAX/BATSE results
  73. GRB 991106, optical observations
  74. GRB991106: the first BeppoSAX short GRB detection?
  75. GRB991105: SAX-GRBM/-WFC detection
  76. GRB 990915 optical observations
  77. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  78. GRB 990806 Optical observations
  79. BeppoSAX NFI Observation of GRB990705
  80. BeppoSAX NFI Observation of GRB990705
  81. Updated Astrometry for the IR Counterpart of GRB990705
  82. Infrared and Optical Observations of GRB990705
  83. GRB990704, optical observations
  84. GRB990704: BeppoSAX detection
  85. GRB 990506 - clarification to GCN 352
  86. GRB 990506 Radio Transient
  87. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  88. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  89. radio detection of X-ray/GRB transient
  90. GRB 990506 R band observations
  91. GRB 990506: BATSE Observations
  92. GRB 990506, optical observations
  93. GRB 990506, optical observations from +1 to +3 hours
  94. GRB990321 IPN TRIANGULATION
  95. GRB 990316 Optical Observations
  96. ASM/IPN error box for GRB 990308 (BATSE #7457)
  97. GRB 990123: Discovery of the Probable Host Galaxy
  98. GRB19990123 observations
  99. GRB 990123 NOT Spectrum Update
  100. GRB990123, 15-GHz limits

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