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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"

28054 results found.

  1. GRB 070129: Swift detection of a burst
  2. GRB 070126: Swift/UVOT refined analysis
  3. GRB 070125: MITSuME Okayama optical observation
  4. GRB 070125: optical observations
  5. GRB 070126: VLT observations
  6. GRB 070124: Suzaku WAM observation of the prompt emissions
  7. GRB 070125: UVOT Detection in Ultraviolet Filters
  8. GRB 070126, Swift-BAT refined analysis of a very faint burst
  9. GRB070125: Optical observation by Kanata
  10. GRB070124: Swift-XRT Observation
  11. Possible GRB 070126: Swift/UVOT Upper Limit
  12. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  13. GRB 070125: Xinglong TNT optical observations
  14. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  15. GRB 070125: Lick 3m Spectroscopy
  16. GRB070125: Swift-XRT Refined Analysis
  17. GRB 070125: SARA detection in R
  18. GRB 070125: P60 Optical Afterglow Candidate
  19. GRB 070126?: Swift detection of a possible burst
  20. GRB070125 redshift request
  21. IPN localization of GRB070124 (short duration, hard spectrum)
  22. GRB 070110: Ep,i - Eiso correlation
  23. GRB 070107: Suzaku WAM observation of the prompt emission
  24. GRB070110: Swift XRT Team refined analysis
  25. GRB 070110, Swift-BAT refined analysis
  26. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  27. GRB 070110: Swift detection of a burst with a possible optical afterglow
  28. GRB 070107: Possible UVOT Afterglow
  29. GRB 070107, Swift-BAT refined analysis
  30. GRB 070107: Swift detection of a burst
  31. VLA observation of GRB 061222B
  32. VLA detection of GRB 061222A
  33. GRB070103: APO SPIcam i' and z' limits
  34. GRB070103: KPNO 4m+FLAMINGOS J limit
  35. GRB 070103: Swift/UVOT Upper limits
  36. GRB070103: Swift XRT refined analysis
  37. GRB 070103, Swift-BAT refined analysis
  38. GRB 070103: NOT observations
  39. GRB 070103: TAROT Calern observatory optical observations
  40. Retractions of previous Swift-BAT triggers
  41. erratum : SDSS Pre-burst Observations of GRB061126
  42. GRB 061210: Swift/XRT Astrometry Correction
  43. GRB 050826: MDM Redshift
  44. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  45. GRB 061222A: Xinglong Optical Limit
  46. GRB 061222A: Gemini Afterglow Candidate
  47. GRB 061222B, Swift-BAT refined analysis
  48. GRB061222A Swift/UVOT: Upper Limits
  49. GRB 061222B: Swift/UVOT Upper limits
  50. GRB 061222B: Observation with the KANATA 1.5m telescope
  51. GRB 061222A: Observation with the KANATA 1.5m telescope
  52. GRB 061222B: BOOTES-IR optical observations
  53. GRB 061222B: SARA upper limit
  54. GRB 061217: Magellan host galaxy redshift
  55. GRB 061222A, Swift-BAT refined analysis
  56. GRB 061222B: REM NIR/optical observations
  57. GRB 061222B: TAROT La Silla observatory optical observations
  58. GRB 061222B: Swift detection of a burst
  59. GRB 061222b: optical afterglow
  60. GRB 061222A: Prompt ROTSE-III Optical Limits
  61. GRB 061222: Swift detection of a burst
  62. GRB 061218: TAROT La Silla observatory optical observations
  63. GRB 061217: TAROT Calern observatory optical observations
  64. GRB 061218: TORTOREM optical upper limits
  65. GRB 061218, Swift-BAT refined analysis
  66. GRB061217: VLT NIR observations
  67. GRB 061218, SMARTS optical/IR observations
  68. GRB 061218: REM prompt observations
  69. Swift triggers (#251863) on a possible burst
  70. GRB061217: Swift/UVOT refined analysis.
  71. GRB 061217: optical observations at Calar Alto
  72. GRB061217 - Swift/XRT refined analysis
  73. GRB 061217, Swift-BAT refined analysis
  74. GRB 061217: Magellan Observations
  75. GRB 061217: REM prompt observations
  76. GRB 061217: ROTSE-III Optical Limits
  77. GRB061210: Swift/UVOT observations
  78. GRB 061210: Swift XRT analysis - Possible counterparts
  79. GRB 061210: Gemini/GMOS Observations
  80. GRB 061126: Radio Observations
  81. GRB061210: Radio Observations
  82. GRB 061202: Suzaku WAM observation of the prompt emission
  83. GRB 061210, Swift-BAT refined analysis of the SHB
  84. Optical Afterglow observations of GRB 061126
  85. GRB 060926: MASTER: discovery of the optical flare
  86. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  87. GRB 061202: TORTOREM optical upper limits
  88. GRB 061201: VLT optical decay
  89. GRB 061201: SOAR Confirmation of Candidate Afterglow
  90. GRB061202: FRAM early follow-up limit
  91. GRB061202 optical limit by "Pi of the Sky"
  92. GRB061202: optical/NIR observations with REM
  93. GRB061202: Swift/UVOT Upper Limits
  94. GRB 061202, Swift-BAT refined analysis
  95. GRB 061202: Swift detection of a burst
  96. GRB 061201: VLT optical observations
  97. GRB 061201: Initial UVOT Observations
  98. GRB 061201, Swift-BAT refined analysis of the SHB
  99. GRB 061201: Swift detection of a short hard burst
  100. INT+WFC observations of GRB 061126

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