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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"

16000 results found.

  1. Skynet observations of GRB 111107A
  2. GRB 111107A: Swift detection of a burst with an optical counterpart
  3. GRB 111103B: MITSuME Akeno Optical upper limits
  4. GRB111103B Swift/UVOT Upper Limits
  5. GRB 111103B: optical observations from TAU, Ka-Dar
  6. Trigger 506913: MASTER detection of Swift J1922.7-1716 optical counterpart
  7. Trigger 506913: Swift detection of Swift J1922.7-1716 and its optical counterpart
  8. GRB 111022B: MASTER OT observations
  9. GRB 111103B: optical observations
  10. GRB 111029A: RAPTOR Limits During the Gamma-ray Emitting Interval
  11. GRB 111029A: SAO RAS optical limits
  12. GRB111029A: MITSuME Ishigakijima Optical Upper Limits
  13. GRB 111029A: TNT optical upper limit, Correction to GCN 12503
  14. GRB 111029A: Swift/UVOT Upper Limits
  15. GRB 111029A: KAIT optical limits
  16. GRB 111029A: TNT optical upper limit
  17. GRB 111029A: optical upper limit
  18. GRB 111029A: ROTSE-III Optical Limits
  19. GRB 111022B: 10.4m GTC z'-band observations
  20. GRB111022B: D50 optical limit
  21. GRB 111022B: BTA Optical Observations
  22. GRB 111022A: MITSuME Akeno Optical upper limits
  23. GRB 111022A: Swift/UVOT Upper Limits
  24. GRB 111016A: optical upper limit
  25. GRB 111022B: Gemini infrared observations
  26. GRB 111022B: MITSuME Akeno Optical upper limits
  27. GRB 111022B: NOT observations
  28. GRB 111022B: MASTER-Net early limit
  29. GRB 111022A: MASTER-Net early limit
  30. GRB 111020A: Gemini-South additional observations and limit on an optical afterglow
  31. GRB 111020A: Swift/UVOT Upper Limits
  32. GRB 111020A: BOOTES-3 Optical Upper Limit.
  33. GRB 111018A: Swift/UVOT Upper Limits
  34. GRB 110918A: Optical light curve for days 1.4 to 16.3
  35. GRB111016A: D50 optical limit
  36. GRB 111016A: Gemini Detection of the NIR Counterpart
  37. GRB 111016A: Swift/UVOT Detection of a Source
  38. GRB 111016A: MITSuME Akeno Optical upper limits
  39. GRB 110921A: optical observations
  40. EVLA 22 GHz Detection of GRB 111008A
  41. GRB 111008A: Swift/UVOT Upper Limits
  42. GRB 111008A: VLT/X-shooter spectroscopy
  43. GRB 111008A: Gemini spectroscopic redshift
  44. GRB 111008A: NOT optical observation
  45. GRB 111008A: Gemini optical counterpart
  46. GRB 111005A: VLT optical observations
  47. GRB 110905A / MAXI J1836-194: optical monitoring
  48. GRB 110921A: MITSuME-Akeno Optical photometry
  49. Skynet observations of GRB 110928A
  50. GRB 110928A: RAPTOR Limits During Gamma-ray Emitting Interval
  51. GRB 110928A: Swift/UVOT Upper Limits
  52. GRB 110825A: GROND Observations
  53. GRB 110928A: ROTSE-III Optical Limits
  54. GRB 110921A: Swift/UVOT Observations
  55. GRB110918A: Lick Observations
  56. GRB 110921A: NOT observations
  57. GRB 110921A: TNT astrometry
  58. GRB 110918A: Liverpool Telescope optical observations
  59. GRB 110921A: optical observations in Mt. Terskol and Maidanak observatories
  60. GRB 110921A: MITSuME Akeno Optical Observation
  61. GRB 110921A : TNT optical counterpart candidate
  62. GRB 110921A: MASTER-Net early limit
  63. GRB 110918A: Swift/UVOT Detection of the Optical Counterpart
  64. GRB 110918A optical observation
  65. GRB 110918A: Gemini-N redshift
  66. GRB 110918A: Afterglow Confirmation from PTF
  67. GRB 110918A: GROND detection of the afterglow candidate
  68. GRB 110918A: INT optical detection of Swift candidate afterglow
  69. GRB110918A: BOOTES-1 optical limit
  70. GRB 110915B: GROND Observations of the Optical/NIR Afterglow Candidate
  71. GRB 110915A: Swift/UVOT Upper Limits
  72. GRB 110915B: Swift/UVOT Upper Limits
  73. GRB 110915A: Deep Gemini-South i/z-band imaging
  74. GRB 110915A: MITSuME Okayama and Ishigakijima Optical upper limits
  75. GRB 110915A: NOT observations
  76. GRB 110915A: GMG optical upper limit
  77. GRB 110915A: MITSuME Akeno Optical upper limits
  78. GRB 110915A: MASTER-Net early limit
  79. GRB 110731A: SAO RAS and Terskol observations
  80. GRB 110905A / X-ray transient MAXI J1836-194: TNT optical observation
  81. GRB 110905A: Potential BAT trigger on MAXI J1836-194
  82. GRB 110903A: Swift/UVOT Upper Limits
  83. GRB 110820A: optical upper limit
  84. GRB 110825A: GMG optical observation
  85. GRB110825A: ROTSE early time optical limit
  86. GRB 110825A: optical afterglow candidate
  87. GRB 110820A: Swift/UVOT Upper Limits
  88. GRB110820A: MITSuME Ishigakijima Optical Upper Limits
  89. GRB 110820A: CrAO optical upper limit
  90. GRB 110820A: MASTER-NET observations
  91. GRB 110818A: Swift/UVOT Upper Limits
  92. GRB 110818A: Optical afterglow and redshift from VLT/X-shooter
  93. GRB 110801A: optical observations at Mt. Terskol observatory
  94. Reprocessed enhanced Swift-XRT positions and GRB products: update
  95. GRB 110808A: VLT/X-shooter spectroscopy
  96. GRB 110808A: Swift detection of a burst with optical counterpart
  97. GRB 110807A: SAO RAS observations
  98. GRB 110726A: two epochs of SAO RAS optical observations
  99. GRB 110801A: optical observations in CrAO
  100. EVLA observation for Fermi burst GRB 110721A

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