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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"

28057 results found.

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

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