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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"

16161 results found.

  1. GRB 090423: WSRT Radio Observations
  2. GRB 090607: Swift/UVOT Upper Limits
  3. GRB 090607: GRAS001 optical observations
  4. GRB 090530: Further NOT optical observations
  5. GRB 090530: RTT150 Optical Observation
  6. GRB 090529A: RTT150 Optical Observations
  7. GRB090529: Further NOT optical observations
  8. GRB 090531b, SMARTS optical/IR observations
  9. GRB 090531B: GROND observation
  10. GRB 090530: Early RAPTOR Optical Observations
  11. GRB090529B: ROVOR Upper Limits
  12. GRB 090531B, RIMOTS optical upper limits
  13. GRB 090531B: Swift/UVOT Upper Limits
  14. GRB 090528B: MASTER-II Kourovka optical limit
  15. GRB 090529: MITSuME optical observation
  16. GRB 090530: GRT Optical Observation
  17. GRB 090531B: ROTSE-III Optical Limits
  18. GRB090530: R-band Observation
  19. GRB 090530: break in light curve
  20. GRB 090529: VLT spectroscopic redshift
  21. GRB 090531: GROND upper limits
  22. GRB 090529: NOT optical observations
  23. GRB 090530: NOT optical observations
  24. GRB 090529: OSN optical observations
  25. GRB 090530: GRAS002 refined OA analysis
  26. GRB 090530: GRAS002 optical observations
  27. GRB 090530: PAIRITEL NIR Detections
  28. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  29. GRB 090530: Swift detection of a burst with an optical counterpart
  30. GRB 090529: optical observations
  31. GRB 090529: TLS Afterglow Observations
  32. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  33. GRB 090529: Xinglong TNT optical observation
  34. GRB090518B optical limit by "Pi of the Sky"
  35. GRB 090516: Fermi GBM observation
  36. GRB 090519: VLT spectroscopic redshift
  37. GRB 090519: Swift/UVOT Upper Limits
  38. GRB 090519: FARO Chante Perdrix Observatory optical observations
  39. GRB 090519: TAROT Calern observatory optical observations
  40. GRB 090518: Swift/UVOT Upper Limits
  41. GRB 090516, RIMOTS optical upper limits
  42. GRB090518 : Optical upper limit by MOA-II telescope
  43. GRB 090516: VLT redshift
  44. GRB 090516 - Zadko Telescope observations
  45. GRB 090516: NOT optical observations
  46. GRB 090516: Faulkes Telescope South optical afterglow
  47. GRB 090515: KAIT optical upper limits
  48. GRB 090515: ROTSE-III Optical Limits
  49. GRB 090510, Radio limits
  50. GRB090510: VLT/FORS2 spectroscopic redshift
  51. GRB 090510: GROND observations
  52. GRB 090510: Swift/UVOT host galaxy candidates
  53. GRB 090510: UVOT refined analysis
  54. GRB 090510: NOT afterglow confirmation
  55. GRB 090509, SMARTS optical/IR afterglow observations
  56. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  57. GRB 090408: optical upper limit
  58. GRB 090418A: optical observation
  59. GRB 090509: REM NIR afterglow
  60. GRB 090323: optical observations
  61. GRB 090423: optical limit
  62. GRB 090424: optical observations
  63. GRB 090424, SMARTS optical/IR afterglow monitoring
  64. GRB 090426: optical observations
  65. GRB 090424: YNAO-GMG observations
  66. GRB 090418A BVRcIc field calibration
  67. GRB 090426: GAO 150cm telescope Optical Observation
  68. GRB 090429B: RIMOTS optical upper limits
  69. GRB 090426: YNAO-GMG observations
  70. GRB 090429B: GROND Observations
  71. GRB 090424 : Multiband Optical observation from Nainital
  72. GRB 090424: Continued R-band monitoring
  73. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  74. GRB 090426: Near infrared observation with ISLE at OAO
  75. GRB 090426: Okayama MITSuME optical observation
  76. GRB 090426 Keck LRIS redshift
  77. GRB090426: Observation for Optical counterpart from MIRO
  78. GRB 090426, RIMOTS optical upper limits
  79. GRB 090426: inspection of SDSS images
  80. GRB 090426: TNT confimation of optical counterpart
  81. GRB 090426: Swift detection of a burst with an optical counterpart
  82. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  83. GRB 090424: MASTER-Net prompt optical limit
  84. GRB 090424 : Lulin 1m telescope optical observations
  85. GRB 090424: THO optical observations
  86. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  87. GRB 090424 Gemini-South Redshift
  88. GRB 090424 : TAOS optical detection
  89. GRB 090424 optical observations
  90. GRB 090424: Liverpool Telescope observations
  91. GRB 090424: Optical observations from 1.23m CAHA
  92. GRB 090424: MASTER-Net prompt optical observations
  93. GRB 090423: Ep,i - Eiso correlation
  94. GRB 090424: TNT optical observations
  95. GRB 090424: ROTSE-III Confimation of Optical Counterpart
  96. GRB 090424: Swift detection of a burst with an optical counterpart
  97. GRB 090423: Near infrared observation at Okayama Observatory
  98. GRB 090423: NOT z-band limit
  99. GRB090418A Rc-band photometry
  100. GRB090423, RIMOTS optical upper limits

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