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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 071117: Las Campanas optical observations
  2. GRB 071117: Swift-XRT refined analysis
  3. GRB 071117, Swift-BAT refined analysis
  4. VLT FORS2 observations of short hard GRB071112B
  5. GRB 071117: Swift/XRT position
  6. GRB 071117: Initial Swift/UVOT observations
  7. GRB 071117: Swift detection of a bright burst
  8. Swift detection of MXB 0656-072
  9. VLA radio upper limit on GRB 071112C
  10. ATCA radio observations of short hard burst GRB 071112B
  11. GRB 071112C: Optical and NIR data observed with KANATA
  12. Correction to the Swift-BAT Transient Identification (trigger=296683)
  13. GRB 071112C: WSRT Radio Observations
  14. GRB071112C: Errata of MITSuME Ic band photometry
  15. GRB 071112C: optical observation
  16. GRB 071112C: optical observation
  17. GRB 071112C: emission lines and refined VLT redshift
  18. GRB 071112C MITSuME Akeno early optical observation
  19. GRB 071112C: Gemini Absorption Redshift
  20. GRB 071112B: 2nd epoch of Magellan i-band imaging
  21. GRB 071112C: SARA upper limit
  22. GRB 071112C : Second Epoch Lulin R-band observations
  23. GRB071112C MITSuME Okayama Optical Observation
  24. GRB 071112C: Swift-BAT refined analysis
  25. GRB 071112C: Swift/UVOT observations
  26. GRB 071112C: Swift XRT refined analysis
  27. GRB 071112C: Optical observations at Crni Vrh
  28. Swift UVOT upper limits of GRB071112B
  29. GRB 071112C: VLT redshift
  30. GRB 071112B: Magellan i-band imaging
  31. GRB 071112B: Gemini Optical Imaging (Correction)
  32. GRB 071112B: Gemini Optical Imaging
  33. GRB 071112B: Swift-XRT preliminary analysis
  34. GRB 071112B, Swift-BAT partial refined analysis of the SHB
  35. GRB071112C: NOT observations
  36. GRB 071112C: Palomar Pre-Imaging
  37. Swift-BAT trigger 296491 is not a GRB
  38. GRB 071112C : Lulin R-band observation
  39. GRB 071112C: RTT150 optical observations
  40. GRB 071112C: TAROT Calern observatory optical observations
  41. Swift XRT follow-up observations of GRB071028B
  42. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  43. GRB 071112C: Optical and NIR afterglows observed with KANATA
  44. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  45. GRB 071112B: ROTSE-III Rapid Optical Limits
  46. GRB 071112C: Swift detection of a burst with an optical counterpart
  47. GRB 071112B: Swift detection of a short hard burst
  48. GRB 071112: Swift detection of a possible burst
  49. GRB071109: Super-LOTIS observations
  50. VLA IInd observation of INTEGRAL burst GRB 071109
  51. Swift/UVOT initial analysis of GRB071109
  52. GRB 071109: further Swift-XRT analysis
  53. GRB 071109: TAROT Calern observatory optical observations
  54. No radio detection at Swift-XRT position
  55. GRB 071109: Swift-XRT possible X-ray counterpart
  56. VLA prompt radio detection of the INTEGRAL burst 071109
  57. GRB 071109: IBIS refined analysis
  58. GRB 071109: BOOTES-2 prompt optical observations
  59. GRB 071109: A long GRB detected by INTEGRAL
  60. GRB 071104: Swift-XRT Team Refined Analysis
  61. GRB 071104: Possible Swift UVOT Afterglow Candidate
  62. GRB 071104: Swift-XRT position
  63. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  64. GRB071010b: optical observation
  65. Swift XRT and UVOT observations of GRB071028B
  66. GRB 071101, Swift-BAT refined analysis
  67. GRB 071101: Swift-XRT Team refined analysis
  68. GRB071101: Optical and NIR upper limits by KANATA
  69. GRB0711101: Two new source from Xinglong TNT observation
  70. GRB 071101: TAROT Calern observatory optical observations
  71. GRB 071101: Swift XRT position
  72. GRB071101 LOAO B,V,R,I observation
  73. GRB 071101: BOOTES-2 prompt optical observations
  74. GRB 071101: a nearby galaxy
  75. GRB 071101: Swift detection of a burst
  76. GRB 071031, Swift-BAT refined analysis
  77. GRB 071031: Swift/UVOT detection of afterglow
  78. GRB 071031: Swift-XRT Team refined analysis
  79. GRB 071020: MITSuME Akeno optical observations
  80. GRB 071031: REM NIR and Optical observation
  81. GRB 071031, SMARTS afterglow observations
  82. GRB 071031: VLT high-resolution spectroscopy
  83. GRB071031: Rapid PROMPT Detections
  84. GRB 071031: GROND detection in all bands
  85. GRB 071031: Swift detection of a burst with an optical counterpart
  86. GRB 071028B Swift-BAT detection of a burst
  87. GRB071025: Optical+NIR observations
  88. GRB 071028: SARA observations of variable source
  89. Swift UVOT upper limits to GRB071028
  90. GRB071028: Xinglong EST V-band upper limit
  91. GRB 071028: Swift-XRT Team refined analysis
  92. GRB 071028, Swift-BAT refined analysis
  93. GRB 071028: Swift detection of a burst
  94. GRB 071025: Kuiper Telescope Optical Observations
  95. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  96. GRB 071018: Revised BAT position
  97. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  98. GRB071021: MARGE Optical Limits
  99. GRB071020, optical upper limit
  100. GRB 071025: SARA VRI upper limits

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