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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"

21795 results found.

  1. GRB 110921A: Enhanced Swift-XRT position
  2. GRB 110921A: MASTER-Net early limit
  3. GRB 110921A: Swift detection of a burst
  4. GRB 110915B : X-ray afterglow confirmation
  5. GRB 110918A: Swift/UVOT Detection of the Optical Counterpart
  6. GRB 110918A optical observation
  7. GRB 110918A: GROND detection of the afterglow candidate
  8. GRB 110918A: INT optical detection of Swift candidate afterglow
  9. GRB 110918A: Swift-XRT observations
  10. Swift detection of short bursts from PSR J1647-4552
  11. GRB 110915A: Konus-Wind and Swift/BAT joint spectral analysis
  12. GRB 110915B: GROND Observations of the Optical/NIR Afterglow Candidate
  13. GRB 110915A: Swift/UVOT Upper Limits
  14. GRB 110915B: Swift/UVOT Upper Limits
  15. GRB 110915A: GROND Upper limits
  16. GRB 110915A, Swift-BAT refined analysis
  17. GRB 110915B: Afterglow candidate from OSN
  18. GRB 110915A: Deep Near-IR Limits from Magellan
  19. GRB 110915B: XRT afterglow candidate
  20. GRB 110903A: Suzaku WAM observation of the prompt emission
  21. GRB 110915A: Deep Gemini-South i/z-band imaging
  22. GRB110915A MITSuME Okayama J-band upper-limit
  23. GRB 110915A: MITSuME Okayama and Ishigakijima Optical upper limits
  24. GRB 110915A: NOT observations
  25. GRB 110915A: 1.23m CAHA I-band observations
  26. GRB 110915A: Enhanced Swift-XRT position
  27. GRB 110915A: GMG optical upper limit
  28. GRB 110915A: MASTER-Net early limit
  29. GRB 110915A: Swift detection of a burst
  30. GRB 110825A: Further Swift/XRT Observations
  31. GRB 110731A: SAO RAS and Terskol observations
  32. GRB 110903A: Swift/UVOT Upper Limits
  33. GRB 110903A: Swift-XRT observations
  34. Konus-Wind observation of GRB 110903A
  35. GRB 110820A: optical upper limit
  36. Trigger 502024: Swift detection of KS 1741-293
  37. GRB110825A: Fermi GBM observation
  38. GRB 110825A: Suzaku WAM observation of the prompt emission
  39. GRB 110825A: GMG optical observation
  40. GRB 110827A, Swift-BAT refined analysis
  41. GRB 110825A: optical afterglow candidate
  42. GRB 110825A: field inspection and possible host galaxy
  43. GRB110825A: Swift target of opportunity observation
  44. IPN triangulation of GRB110825A (very intense, long-duration)
  45. Swift-BAT Trigger 501485 is noise
  46. Konus-Wind observation of GRB 110820B
  47. GRB 110820A: MASTER-NET first hour observations
  48. IPN triangulation of GRB 110820B (very long duration, extremely intense)
  49. GRB 110820A: Swift/UVOT Upper Limits
  50. GRB110820A: MITSuME Ishigakijima Optical Upper Limits
  51. GRB 110820A: Swift-BAT refined analysis
  52. GRB 110820A: Enhanced Swift-XRT position
  53. GRB 110820A: CrAO optical upper limit
  54. GRB 110820A: MASTER-NET observations
  55. GRB 110820A: Swift detection of a burst
  56. GRB 110818A: Swift/UVOT Upper Limits
  57. GRB 110818A: Enhanced Swift-XRT position
  58. GRB 110818A: Optical afterglow and redshift from VLT/X-shooter
  59. GRB 110818A: Swift-XRT refined Analysis
  60. GRB 110815A: Swift-XRT and UVOT refined Analysis
  61. GRB 110815A : Suzaku WAM observation of the prompt emission
  62. GRB 110818A: Swift detection of a burst
  63. Konus-Wind observation of GRB 110815A
  64. IPN triangulation of GRB110815A (long, intense)
  65. GRB 110801A: optical observations at Mt. Terskol observatory
  66. Reprocessed enhanced Swift-XRT positions and GRB products: update
  67. Konus-Wind observation of GRB 110808B
  68. Konus-Wind observation of GRB 110808A
  69. IPN triangulation of GRB 110808B (short/hard/intense)
  70. RXTE Discovery of the Spin Period of Swift J1834.9-0846
  71. GRB 110808A: Swift/UVOT Detection
  72. SGR J1834.9-0846: A Neutron Star in W41?
  73. GRB 110808A: Enhanced Swift-XRT position
  74. GRB 110808A: Swift detection of a burst with optical counterpart
  75. GRB 110807A: SAO RAS observations
  76. GRB 110807A: Swift detection of a burst or a posible new SGR
  77. GRB 110726A: two epochs of SAO RAS optical observations
  78. Konus-Wind observation of GRB 110802A
  79. IPN triangulation of GRB110802A (short/hard burst)
  80. GRB 110801A: optical observations in CrAO
  81. EVLA observation for Fermi burst GRB 110721A
  82. GRB 110731A : Suzaku WAM observation of the prompt emission
  83. GRB 110801A: SAO RAS optical observations
  84. GRB110801A: MITSuME Ishigakijima Optical Observation at 1 day after the burst
  85. Swift/UVOT observations of GRB110801A
  86. GRB110801A: MITSuME Ishigakijima Optical Observation
  87. GRB 110801A: Enhanced Swift-XRT position
  88. GRB 110801A: Swift detection of a burst with an optical counterpart
  89. GRB110731A: MITSuME Ishigakijima Optical Upper Limits
  90. Konus-Wind observation of GRB 110731A
  91. GRB110731A: Swift/UVOT Observations
  92. GRB 110731A: NOT photometry
  93. GRB 110731A: Enhanced Swift-XRT position
  94. GRB 110731A: Swift detection of a burst with an optical counterpart
  95. Sw J1644+57 (GRB 110328A): Continued VLBA Observations
  96. INTEGRAL Weak trigger #6331: GRT Optical Observation
  97. GRB 110721A: Swift observations of afterglow candidate
  98. AXP 4U 0142+61: Swift-BAT refined analysis
  99. GRB 110726A: optical upper limit in CrAO
  100. Swift detection of a SGR-like burst from the AXP 4U 0142+61

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