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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"

23403 results found.

  1. GRB 111022B: EVLA observations - correction to GCN 12495
  2. GRB 111022B: EVLA observations
  3. GRB 111022B: 10.4m GTC z'-band observations
  4. GRB111022B: D50 optical limit
  5. GRB 111020A: Chandra Observation
  6. GRB 111022B: BTA Optical Observations
  7. GRB 111022B: Swift/UVOT upper limits
  8. GRB 111022A: Swift/UVOT Upper Limits
  9. GRB 111016A: optical upper limit
  10. GRB 111022B: NOT observations
  11. GRB 111022B: Enhanced Swift-XRT position
  12. GRB 111022A: Preliminary UVOT TDRSS Non-Detection
  13. GRB 111022B: Swift detection of a burst
  14. GRB 111022A: Swift detection of a burst
  15. GRB 111020A: Gemini-South additional observations and limit on an optical afterglow
  16. GRB 111020A: EVLA observations
  17. GRB 111020A: Gemini-South i-band observations
  18. GRB 111020A: Swift/UVOT Upper Limits
  19. GRB 111020A: Enhanced Swift-XRT position
  20. GRB 111020A: BOOTES-3 Optical Upper Limit.
  21. GRB 111020A: Swift detection of a short burst
  22. GRB 111018A: Swift/UVOT Upper Limits
  23. GRB 111018A: GROND Upper Limits
  24. GRB 111018A: Enhanced Swift-XRT position
  25. IPN Triangulation of GRB 111016B (long duration, intense)
  26. GRB111016A : WIYN 3.5m NIR observations
  27. GRB 111018A: Swift detection of a burst
  28. GRB 111017A: Fermi GBM Detection
  29. GRB111016A: D50 optical limit
  30. GRB 111016A: Gemini Detection of the NIR Counterpart
  31. GRB 111016A: Swift/UVOT Detection of a Source
  32. GRB 111016A: P60 Afterglow Candidate
  33. GRB 111016A: Enhanced Swift-XRT position
  34. GRB 111016A: Swift-XRT observations
  35. GRB 111016A: Swift detection of a burst
  36. GRB 110921A: optical observations
  37. GRB 111008A: Swift/UVOT Upper Limits
  38. GRB 111008A: IAC80 I-band observations
  39. GRB 111008A, GROND observations
  40. GRB 111008A: NOT optical observation
  41. GRB 111008A: Gemini optical counterpart
  42. GRB 111008A: Enhanced Swift-XRT position
  43. GRB 111008A: Swift detection of a burst
  44. GRB 111005A: ATCA 18 GHz detection
  45. GRB 111005A: ATCA radio upper limit
  46. GRB 111005A : miniTAO/ANIR NIR observations
  47. GRB 111005A: GROND NIR observations
  48. GRB 111005A: VLT IR observations
  49. GRB 111005A: Swift detection of a burst
  50. GRB 111003A: Fermi GBM detection
  51. GRB 110921A: MITSuME-Akeno Optical photometry
  52. Skynet/Dolomiti observations of GRB 110928A
  53. Skynet observations of GRB 110928A
  54. GRB 110928A: RAPTOR Limits During Gamma-ray Emitting Interval
  55. GRB 110928A: Swift/UVOT Upper Limits
  56. Trigger 504307: Swift detection of MAXI J1836-194
  57. GRB 110825A: GROND Observations
  58. GRB 110928A: Enhanced Swift-XRT position
  59. GRB 110928A: P60 Observations
  60. GRB 110928A: Further PAIRITEL NIR Observations
  61. GRB 110928A: Swift-XRT observations
  62. GRB 110928A: Swift/UVOT finding chart observation
  63. GRB 110928A: PAIRITEL NIR Observations
  64. GRB 110928A: ROTSE-III Optical Limits
  65. GRB 110928A: Swift detection of a burst
  66. Swift-BAT trigger 503926 is noise
  67. GRB 110924A: Swift detection of a possible burst
  68. GCN for GRB 110921B
  69. GRB 110921A: Swift/UVOT Observations
  70. GRB 110921A: NOT observations
  71. GRB 110921A: TNT astrometry
  72. GRB 110918A: submm observations from APEX
  73. GRB 110921A: optical observations in Mt. Terskol and Maidanak observatories
  74. GRB 110921A: Enhanced Swift-XRT position
  75. GRB 110921A: Swift detection of a burst
  76. GRB 110915B : X-ray afterglow confirmation
  77. GRB 110918A: Swift/UVOT Detection of the Optical Counterpart
  78. GRB 110918A optical observation
  79. GRB 110918A: GROND detection of the afterglow candidate
  80. GRB 110918A: INT optical detection of Swift candidate afterglow
  81. GRB 110918A: Swift-XRT observations
  82. Swift detection of short bursts from PSR J1647-4552
  83. GRB 110915A: Konus-Wind and Swift/BAT joint spectral analysis
  84. IPN triangulation of GRB 110918A (long duration, extremely intense)
  85. GRB 110915B: GROND Observations of the Optical/NIR Afterglow Candidate
  86. GRB 110915A: Swift/UVOT Upper Limits
  87. GRB 110915B: Swift/UVOT Upper Limits
  88. GRB 110915A: GROND Upper limits
  89. GRB 110915B: Afterglow candidate from OSN
  90. GRB 110915A: Deep Near-IR Limits from Magellan
  91. GRB 110915B: XRT afterglow candidate
  92. GRB 110915A: Deep Gemini-South i/z-band imaging
  93. GRB110915A MITSuME Okayama J-band upper-limit
  94. GRB 110915A: MITSuME Okayama and Ishigakijima Optical upper limits
  95. GRB 110915A: NOT observations
  96. GRB 110915A: 1.23m CAHA I-band observations
  97. GRB 110915A: Enhanced Swift-XRT position
  98. GRB 110915A: GMG optical upper limit
  99. GRB 110915A: MASTER-Net early limit
  100. GRB 110915A: Swift detection of a burst

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