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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"

23417 results found.

  1. GRB 070311: Optical observation.
  2. GRB 070306: possible emission-line redshift
  3. GRB 070311: SARA upper limit
  4. GRB 070311: RAPTOR Detection of Optical Emission
  5. GRB070311: FRAM early follow-up limit
  6. GRB 070311: P60 Observations
  7. GRB 070311: Swift/UVOT Upper Limits
  8. GRB 070311: MITSuME Okayama Optical Observation
  9. GRB 070311: Swift-XRT refined analysis
  10. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  11. GRB 070311: REM candidate afterglow
  12. GRB060901: Candidate optical afterglow
  13. GRB070309: Swift/XRT possible afterglow detection
  14. GRB 070125: Chandra X-ray Confirmation of Jet Break
  15. GRB 070309: Swift/UVOT Upper Limits
  16. GRB 070306, optical observation
  17. Swift UVOT Finding Charts for GRB 070309
  18. VLA observation of GRB 070306
  19. GRB 070306: NOT observations
  20. GRB 070306 Swift/UVOT refined analysis
  21. GRB 070306: ART-3 early optical and near infrared constraints
  22. GRB 070306: IR observations and candidate afterglow
  23. GRB 070306: Optical and IR observations with KANATA
  24. GRB070306 - SDSS Pre-burst Observations
  25. GRB 070306: Swift detection of a burst
  26. GRB 060605 new redshift
  27. GRB 070125, deep late-time optical observation
  28. VLA observation of GRB 070224
  29. GRB 070227: Swift/UVOT Upper Limits
  30. GRB 070227: TAROT La Silla observatory optical observations
  31. GRB 070227, Swift-BAT refined analysis
  32. GRB 070227: Swift detection of a burst in ground analysis
  33. GRB 920925C: optical afterglow candidate
  34. GRB 070224: Swift/UVOT Upper Limits
  35. VLA observation of GRB 070223
  36. VLA observation of GRB 070220
  37. GRB070224: Magellan Imaging Observations
  38. GRB 070224: WHT K-band imaging
  39. GRB 070224: MDM Observations
  40. GRB070224: Gemini Imaging Observations
  41. GRB 070224: SARA upper limit
  42. GRB070224: Swift-XRT Refined Analysis
  43. GRB 070224: optical afterglow candidate
  44. GRB 070224: MASTER-Net refind analysis
  45. GRB 070224: MASTER-VWF-Kislovodsk observations
  46. GRB 070224: Swift detection of a burst
  47. GRB 070223: Optical observations
  48. GRB070223: Swift/UVOT refined analysis
  49. GRB 070223: Optical-IR observation with KANATA
  50. GRB070223: MASTER-VWF-Kislovodsk observations
  51. GRB070223 - SDSS Pre-Burst Observations
  52. GRB070223: Swift burst
  53. GRB 070220: MITSuME Okayama Optical Observation
  54. GRB 070220: ART-3 Optical and NIR limits
  55. Swift/UVOT refined analysis of GRB070220
  56. GRB 070209: Swift XRT refined analysis
  57. GRB 070220: Observation with the KANATA 1.5m telescope
  58. GRB 070219: Gemini Observations
  59. GRB 070220: Swift detection of a burst
  60. GRB070219: MASTER-VWF-Kislovodsk observations
  61. GRB 070219: Swift/UVOT Upper limits
  62. GRB 070219: I-band observations
  63. GRB 070219: optical TNG observations
  64. GRB 070219: ROTSE-III Optical Limits
  65. GRB070219 - SDSS Pre-Burst Observations
  66. GRB 070219: Swift detection of a burst
  67. GRB 070125 observations with the GMRT
  68. GRB 060927: PROMPT Observations
  69. GRB 070129: MDM I-band Detection
  70. GRB 070209: Swift XRT analysis
  71. IPN localization of very bright long hard GRB 070207
  72. IPN localization of very intense short GRB 070201
  73. GRB 070209: Swift detection of a short hard burst
  74. GRB070208 - SDSS Pre-Burst Observations
  75. GRB 070208: Swift detection of a burst
  76. GRB 070125 detection with CARMA
  77. GRB 070129: afterglow confirmation
  78. GRB070126: Swift-XRT Observation
  79. GRB 070129: Swift/UVOT Upper limits
  80. GRB070129: MITSuME optical observation
  81. GRB 070129: Xinglong TNT optical Upper Limit
  82. GRB 070129: Swift-XRT Refined Analysis
  83. GRB 070129: VLT observations
  84. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  85. GRB 070129: Swift detection of a burst
  86. GRB 070126: Swift/UVOT refined analysis
  87. GRB 070125: optical observations
  88. GRB 070126: VLT observations
  89. GRB070126: Swift-XRT possible detection of an afterglow
  90. GRB070125: Optical observation by Kanata
  91. GRB070124: Swift-XRT Observation
  92. Possible GRB 070126: Swift/UVOT Upper Limit
  93. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  94. GRB 070125: Xinglong TNT optical observations
  95. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  96. GRB 070125: Lick 3m Spectroscopy
  97. GRB070125: Swift-XRT Refined Analysis
  98. GRB 070125: SARA detection in R
  99. GRB 070125: P60 Optical Afterglow Candidate
  100. GRB 070126?: Swift detection of a possible burst

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