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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"

31727 results found.

  1. GRB 071227: VLT probable redshift of the candidate host galaxy
  2. GRB 071227: Magellan observations
  3. GRB071227: Swift/UVOT refined analysis
  4. GRB 071227: REM NIR and Optical observations
  5. Swift-BAT refined analysis of short GRB 071227
  6. GRB071020: optical observations
  7. GRB 070429B: Possible UVOT Detection of an Optical Afterglow
  8. Swift-BAT trigger 298308 is not a GRB
  9. GRB 071125: Suzaku WAM observation of the prompt emission
  10. GRB 070429B: Probable host galaxy and redshift
  11. GRB 071129, Swift-BAT refined analysis
  12. Konus-Wind and Konus-A observations of GRB 071125
  13. GRB 071112C: Optical/NIR observations
  14. Disregard the "GRB 071126" position
  15. VLA radio detection of GRB 071122
  16. GRB071122: Swift/UVOT Observations
  17. GRB071104: NIR Afterglow Candidate at TNG
  18. GRB 071122: MASTER optical observation
  19. GRB 071122, Swift-BAT refined analysis
  20. GRB 071122 Swift XRT position update sent in error.
  21. GRB 071122 Swift-XRT refined analysis
  22. GRB 071122: Corrected P60 Coordinates
  23. GRB071122: Gemini Absorption redshift
  24. GRB 071122: P60 Optical Afterglow Candidate
  25. GRB 071122: ROTSE-III Optical Limits
  26. GRB 071118: P60 Observations
  27. GRB071118 MITSuME OAO optical observation
  28. GRB 071118: Observations from OSN
  29. GRB 071117: VLT observations and probable redshift
  30. Swift/UVOT observations of GRB071118
  31. GRB 071117: Swift-XRT revised position
  32. Konus-Wind and Konus-A observations of GRB 071117
  33. Swift XRT follow-up observations of GRB071008
  34. Swift/UVOT upper limits for GRB 071117
  35. GRB071118: Swift XRT refined analysis
  36. GRB 071117: Gemini Optical Afterglow Discovery
  37. GRB 071118, Swift-BAT refined analysis
  38. GRB 071112B: Gemini Image Differencing
  39. GRB 071117: Gemini Observations
  40. GRB 071117: Swift-XRT refined analysis
  41. GRB 071117, Swift-BAT refined analysis
  42. VLT FORS2 observations of short hard GRB071112B
  43. GRB 071117: Swift/XRT position
  44. VLA radio upper limit on GRB 071112C
  45. ATCA radio observations of short hard burst GRB 071112B
  46. GRB 071112C: Optical and NIR data observed with KANATA
  47. Correction to the Swift-BAT Transient Identification (trigger=296683)
  48. GRB 071112C: WSRT Radio Observations
  49. GRB071112C: Errata of MITSuME Ic band photometry
  50. GRB 071112C: optical observation
  51. GRB 071112C: optical observation
  52. GRB 071112C: emission lines and refined VLT redshift
  53. GRB 071112C MITSuME Akeno early optical observation
  54. GRB 071112C: Gemini Absorption Redshift
  55. GRB 071112B: 2nd epoch of Magellan i-band imaging
  56. GRB 071112C: SARA upper limit
  57. GRB 071112C : Second Epoch Lulin R-band observations
  58. GRB071112C MITSuME Okayama Optical Observation
  59. GRB 071112C: Swift-BAT refined analysis
  60. GRB 071112C: Swift/UVOT observations
  61. GRB 071112C: Swift XRT refined analysis
  62. GRB 071112C: Optical observations at Crni Vrh
  63. Swift UVOT upper limits of GRB071112B
  64. GRB 071112C: VLT redshift
  65. GRB 071112B: Magellan i-band imaging
  66. GRB 071112B: Gemini Optical Imaging (Correction)
  67. GRB 071112B: Gemini Optical Imaging
  68. GRB 071112B: Swift-XRT preliminary analysis
  69. GRB 071112B, Swift-BAT partial refined analysis of the SHB
  70. GRB071112C: NOT observations
  71. GRB 071112C: Palomar Pre-Imaging
  72. Swift-BAT trigger 296491 is not a GRB
  73. GRB 071112C : Lulin R-band observation
  74. GRB 071112C: RTT150 optical observations
  75. Swift XRT follow-up observations of GRB071028B
  76. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  77. GRB 071112C: Optical and NIR afterglows observed with KANATA
  78. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  79. GRB 071112B: ROTSE-III Rapid Optical Limits
  80. GRB071109: Super-LOTIS observations
  81. VLA IInd observation of INTEGRAL burst GRB 071109
  82. Swift/UVOT initial analysis of GRB071109
  83. GRB 071109: further Swift-XRT analysis
  84. No radio detection at Swift-XRT position
  85. GRB 071109: Swift-XRT possible X-ray counterpart
  86. VLA prompt radio detection of the INTEGRAL burst 071109
  87. GRB 071109: IBIS refined analysis
  88. GRB 071109: BOOTES-2 prompt optical observations
  89. GRB 071104: Swift-XRT Team Refined Analysis
  90. GRB 071104: Possible Swift UVOT Afterglow Candidate
  91. GRB 071104: Swift-XRT position
  92. GRB071010b: optical observation
  93. Swift XRT and UVOT observations of GRB071028B
  94. GRB 071101, Swift-BAT refined analysis
  95. GRB 071101: Swift-XRT Team refined analysis
  96. GRB071101: Optical and NIR upper limits by KANATA
  97. GRB0711101: Two new source from Xinglong TNT observation
  98. GRB 071101: TAROT Calern observatory optical observations
  99. GRB 071101: Swift XRT position
  100. GRB 071101: BOOTES-2 prompt optical observations

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