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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"

15742 results found.

  1. GRB 090529: VLT spectroscopic redshift
  2. GRB 090531: GROND upper limits
  3. GRB 090529: NOT optical observations
  4. GRB 090530: NOT optical observations
  5. GRB 090529: OSN optical observations
  6. GRB 090530: GRAS002 refined OA analysis
  7. GRB 090530: GRAS002 optical observations
  8. GRB 090530: PAIRITEL NIR Detections
  9. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  10. GRB 090530: Swift detection of a burst with an optical counterpart
  11. GRB 090529: optical observations
  12. GRB 090529: TLS Afterglow Observations
  13. GRB090529: UVOT/Swift detection of a brightening optical afterglow
  14. GRB 090529: Xinglong TNT optical observation
  15. GRB090518B optical limit by "Pi of the Sky"
  16. GRB 090516: Fermi GBM observation
  17. GRB 090519: VLT spectroscopic redshift
  18. GRB 090519: Swift/UVOT Upper Limits
  19. GRB 090519: FARO Chante Perdrix Observatory optical observations
  20. GRB 090519: TAROT Calern observatory optical observations
  21. GRB 090518: Swift/UVOT Upper Limits
  22. GRB 090516, RIMOTS optical upper limits
  23. GRB090518 : Optical upper limit by MOA-II telescope
  24. GRB 090516: VLT redshift
  25. GRB 090516 - Zadko Telescope observations
  26. GRB 090516: NOT optical observations
  27. GRB 090516: Faulkes Telescope South optical afterglow
  28. GRB 090515: KAIT optical upper limits
  29. GRB 090515: ROTSE-III Optical Limits
  30. GRB 090510, Radio limits
  31. GRB090510: VLT/FORS2 spectroscopic redshift
  32. GRB 090510: GROND observations
  33. GRB 090510: Swift/UVOT host galaxy candidates
  34. GRB 090510: UVOT refined analysis
  35. GRB 090510: NOT afterglow confirmation
  36. GRB 090509, SMARTS optical/IR afterglow observations
  37. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  38. GRB 090408: optical upper limit
  39. GRB 090418A: optical observation
  40. GRB 090509: REM NIR afterglow
  41. GRB 090323: optical observations
  42. GRB 090423: optical limit
  43. GRB 090424: optical observations
  44. GRB 090424, SMARTS optical/IR afterglow monitoring
  45. GRB 090426: optical observations
  46. GRB 090424: YNAO-GMG observations
  47. GRB 090418A BVRcIc field calibration
  48. GRB 090426: GAO 150cm telescope Optical Observation
  49. GRB 090429B: RIMOTS optical upper limits
  50. GRB 090426: YNAO-GMG observations
  51. GRB 090429B: GROND Observations
  52. GRB 090424 : Multiband Optical observation from Nainital
  53. GRB 090424: Continued R-band monitoring
  54. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  55. GRB 090426: Near infrared observation with ISLE at OAO
  56. GRB 090426: Okayama MITSuME optical observation
  57. GRB 090426 Keck LRIS redshift
  58. GRB090426: Observation for Optical counterpart from MIRO
  59. GRB 090426, RIMOTS optical upper limits
  60. GRB 090426: inspection of SDSS images
  61. GRB 090426: TNT confimation of optical counterpart
  62. GRB 090426: Swift detection of a burst with an optical counterpart
  63. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  64. GRB 090424: MASTER-Net prompt optical limit
  65. GRB 090424 : Lulin 1m telescope optical observations
  66. GRB 090424: THO optical observations
  67. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  68. GRB 090424 Gemini-South Redshift
  69. GRB 090424 : TAOS optical detection
  70. GRB 090424 optical observations
  71. GRB 090424: Liverpool Telescope observations
  72. GRB 090424: Optical observations from 1.23m CAHA
  73. GRB 090424: MASTER-Net prompt optical observations
  74. GRB 090423: Ep,i - Eiso correlation
  75. GRB 090424: TNT optical observations
  76. GRB 090424: ROTSE-III Confimation of Optical Counterpart
  77. GRB 090424: Swift detection of a burst with an optical counterpart
  78. GRB 090423: Near infrared observation at Okayama Observatory
  79. GRB 090423: NOT z-band limit
  80. GRB090418A Rc-band photometry
  81. GRB090423, RIMOTS optical upper limits
  82. GRB 090423: P60 Observations
  83. GRB 090418A: R and I band observation
  84. GRB 090418B: RTT150 optical observations
  85. GRB 090418A: RTT150 optical observations
  86. GRB 080410: GAO 150cm telescope Optical Observation
  87. GRB 080408A: GAO 150cm telescope Optical Observation
  88. GRB 090417B: Optical observation
  89. GRB 090418A: optical observations
  90. GRB 090418A: Swift/UVOT Observations
  91. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  92. GRB 090419: Swift-BAT refined analysis
  93. VLA radio detection of GRB 090418
  94. GRB 090418A: ROTSE-III Refined Analysis
  95. GRB 090418: PAIRITEL NIR detection
  96. GRB 090418 Lick Redshift
  97. GRB 090418: ROTSE-III Confirmation of Optical Counterpart
  98. GRB 090418: Swift detection of a burst with optical afterglow
  99. GRB 090417B: MITSuME Okayama optical upper limits
  100. GRB090417B: Xinglong TNT optical upper limit

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