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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"
  1. GRB 071118: Swift detection of a burst
  2. GRB 071117: Gemini Observations
  3. GRB 071117: Las Campanas optical observations
  4. GRB 071117: Swift-XRT refined analysis
  5. GRB 071117, Swift-BAT refined analysis
  6. VLT FORS2 observations of short hard GRB071112B
  7. GRB 071117: Swift/XRT position
  8. GRB 071117: Initial Swift/UVOT observations
  9. GRB 071117: Swift detection of a bright burst
  10. Swift detection of MXB 0656-072
  11. VLA radio upper limit on GRB 071112C
  12. ATCA radio observations of short hard burst GRB 071112B
  13. GRB 071112C: Optical and NIR data observed with KANATA
  14. Correction to the Swift-BAT Transient Identification (trigger=296683)
  15. GRB 071112C: WSRT Radio Observations
  16. GRB071112C: Errata of MITSuME Ic band photometry
  17. GRB 071112C: optical observation
  18. GRB 071112C: optical observation
  19. GRB 071112C: emission lines and refined VLT redshift
  20. GRB 071112C MITSuME Akeno early optical observation
  21. GRB 071112C: Gemini Absorption Redshift
  22. GRB 071112B: 2nd epoch of Magellan i-band imaging
  23. GRB 071112C: SARA upper limit
  24. GRB 071112C : Second Epoch Lulin R-band observations
  25. GRB071112C MITSuME Okayama Optical Observation
  26. GRB 071112C: Swift-BAT refined analysis
  27. GRB 071112C: Swift/UVOT observations
  28. GRB 071112C: Swift XRT refined analysis
  29. GRB 071112C: Optical observations at Crni Vrh
  30. Swift UVOT upper limits of GRB071112B
  31. GRB 071112C: VLT redshift
  32. GRB 071112B: Magellan i-band imaging
  33. GRB 071112B: Gemini Optical Imaging (Correction)
  34. GRB 071112B: Gemini Optical Imaging
  35. GRB 071112B: Swift-XRT preliminary analysis
  36. GRB 071112B, Swift-BAT partial refined analysis of the SHB
  37. GRB071112C: NOT observations
  38. GRB 071112C: Palomar Pre-Imaging
  39. Swift-BAT trigger 296491 is not a GRB
  40. GRB 071112C : Lulin R-band observation
  41. GRB 071112C: RTT150 optical observations
  42. GRB 071112C: TAROT Calern observatory optical observations
  43. Swift XRT follow-up observations of GRB071028B
  44. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  45. GRB 071112C: Optical and NIR afterglows observed with KANATA
  46. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  47. GRB 071112B: ROTSE-III Rapid Optical Limits
  48. GRB 071112C: Swift detection of a burst with an optical counterpart
  49. GRB 071112B: Swift detection of a short hard burst
  50. GRB 071112: Swift detection of a possible burst
  51. GRB071109: Super-LOTIS observations
  52. VLA IInd observation of INTEGRAL burst GRB 071109
  53. Swift/UVOT initial analysis of GRB071109
  54. GRB 071109: further Swift-XRT analysis
  55. GRB 071109: TAROT Calern observatory optical observations
  56. No radio detection at Swift-XRT position
  57. GRB 071109: Swift-XRT possible X-ray counterpart
  58. VLA prompt radio detection of the INTEGRAL burst 071109
  59. GRB 071109: IBIS refined analysis
  60. GRB 071109: BOOTES-2 prompt optical observations
  61. GRB 071109: A long GRB detected by INTEGRAL
  62. GRB 071104: Swift-XRT Team Refined Analysis
  63. GRB 071104: Possible Swift UVOT Afterglow Candidate
  64. GRB 071104: Swift-XRT position
  65. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  66. GRB071010b: optical observation
  67. Swift XRT and UVOT observations of GRB071028B
  68. GRB 071101, Swift-BAT refined analysis
  69. GRB 071101: Swift-XRT Team refined analysis
  70. GRB071101: Optical and NIR upper limits by KANATA
  71. GRB0711101: Two new source from Xinglong TNT observation
  72. GRB 071101: TAROT Calern observatory optical observations
  73. GRB 071101: Swift XRT position
  74. GRB071101 LOAO B,V,R,I observation
  75. GRB 071101: BOOTES-2 prompt optical observations
  76. GRB 071101: a nearby galaxy
  77. GRB 071101: Swift detection of a burst
  78. GRB 071031, Swift-BAT refined analysis
  79. GRB 071031: Swift/UVOT detection of afterglow
  80. GRB 071031: Swift-XRT Team refined analysis
  81. GRB 071020: MITSuME Akeno optical observations
  82. GRB 071031: REM NIR and Optical observation
  83. GRB 071031, SMARTS afterglow observations
  84. GRB 071031: VLT high-resolution spectroscopy
  85. GRB071031: Rapid PROMPT Detections
  86. GRB 071031: GROND detection in all bands
  87. GRB 071031: Swift detection of a burst with an optical counterpart
  88. GRB 071028B Swift-BAT detection of a burst
  89. GRB071025: Optical+NIR observations
  90. GRB 071028: SARA observations of variable source
  91. Swift UVOT upper limits to GRB071028
  92. GRB071028: Xinglong EST V-band upper limit
  93. GRB 071028: Swift-XRT Team refined analysis
  94. GRB 071028, Swift-BAT refined analysis
  95. GRB 071028: Swift detection of a burst
  96. GRB 071025: Kuiper Telescope Optical Observations
  97. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  98. GRB 071018: Revised BAT position
  99. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  100. GRB071021: MARGE Optical Limits

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