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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"

8474 results found.

  1. GRB 111121A: Magellan/Megacam observations
  2. GRB 111117A: Chandra detection of the afterglow
  3. GRB 111121A: Swift detection of a short hard burst
  4. GRB 111117A: Gemini Afterglow Limits
  5. GRB 111117A: GROND observations
  6. GRB 111117A: Swift detection of a short hard burst
  7. GRB 111107A: Fermi GBM observation
  8. GRB 111107A: VLT/X-shooter spectroscopy
  9. GRB 111107A: GROND observations
  10. GRB 111107A: Swift detection of a burst with an optical counterpart
  11. GRB 111103B : WIYN 3.5m NIR observations
  12. Trigger 506913: Swift detection of Swift J1922.7-1716 and its optical counterpart
  13. GRB 111103B: Swift detection of a strong burst from a GRB or Galactic source
  14. GRB 111029A: SAO RAS optical limits
  15. GRB 111029A: Swift detection of a burst
  16. GRB 111022B: 10.4m GTC z'-band observations
  17. GRB 111022A: RIzY Observation
  18. GRB 111020A Spectral lag analysis
  19. GRB 111022A: Preliminary UVOT TDRSS Non-Detection
  20. GRB 111022B: Swift detection of a burst
  21. GRB 111020A: Gemini-South i-band observations
  22. GRB 111020A: Swift detection of a short burst
  23. GRB 110918A: Optical light curve for days 1.4 to 16.3
  24. GRB 111018A: Swift detection of a burst
  25. GRB 111017A: Fermi GBM Detection
  26. GRB 111016A: Gemini Detection of the NIR Counterpart
  27. GRB 111016A: P60 Afterglow Candidate
  28. GRB 111016A: Swift detection of a burst
  29. EVLA 22 GHz Detection of GRB 111008A
  30. GRB 111008A: Gemini spectroscopic redshift
  31. GRB 111008A: Swift detection of a burst
  32. GRB 110928A: Swift-BAT refined analysis
  33. GRB 110928A: Swift/UVOT finding chart observation
  34. GRB 110928A: Swift detection of a burst
  35. GRB 110924A: Swift detection of a possible burst
  36. GRB 110918A: submm observations from APEX
  37. GRB 110921A: optical observations in Mt. Terskol and Maidanak observatories
  38. GRB 110921A: MITSuME Akeno Optical Observation
  39. GRB 110921A : TNT optical counterpart candidate
  40. GRB 110921A: Swift detection of a burst
  41. GRB 110918A: Gemini-N redshift
  42. GRB 110918A: Afterglow Confirmation from PTF
  43. GRB 110918A: GROND detection of the afterglow candidate
  44. GRB 110918A: INT optical detection of Swift candidate afterglow
  45. Swift detection of short bursts from PSR J1647-4552
  46. GRB 110915B: GROND Observations of the Optical/NIR Afterglow Candidate
  47. GRB 110915B: Afterglow candidate from OSN
  48. GRB 110915B: XRT afterglow candidate
  49. GRB 110915B: SuperAGILE localization of a long GRB
  50. GRB 110915A: Swift detection of a burst
  51. GRB 110825A: GMG optical observation
  52. GRB 110825A: optical afterglow candidate
  53. Swift-BAT Trigger 501485 is noise
  54. GRB 110820A: Swift/UVOT Upper Limits
  55. GRB 110820A: Position udpate + 2nd epoch data
  56. GRB 110820A: Swift detection of a burst
  57. GRB 110818A: Optical afterglow and redshift from VLT/X-shooter
  58. GRB 110818A: Swift detection of a burst
  59. GRB 110812A: SuperAGILE localization of a long GRB.
  60. SGR J1834.9-0846: A Neutron Star in W41?
  61. GRB 110808A: VLT/X-shooter spectroscopy
  62. GRB 110808A: Swift detection of a burst with optical counterpart
  63. Fermi GBM detection of a SGR-like burst
  64. GRB 110807A: Swift detection of a burst or a posible new SGR
  65. GRB 110801A: Swift detection of a burst with an optical counterpart
  66. GRB 110731A: FTN+FTS afterglow observations
  67. GRB 110731A: Swift detection of a burst with an optical counterpart
  68. GRB 110721A: Swift observations of afterglow candidate
  69. Swift detection of a SGR-like burst from the AXP 4U 0142+61
  70. GRB 110726A: Swift/UVOT Detection
  71. GRB 110726A: Liverpool Telescope observations
  72. GRB 110726A: Swift detection of a burst
  73. IPN triangulation of GRB 110721A
  74. GRB 110721A: Gemini-South spectroscopy of the potential optical counterpart
  75. GRB 110721A: potential counterpart candidate
  76. Konus-Wind observation of GRB 110721A
  77. GRB 110719A: Swift-BAT refined analysis
  78. GRB 110719A: Swift detection of a burst
  79. Swift J1822.3-1606: Transient Magnetar or Be X-ray Binary?
  80. Swift J1822.3-1606
  81. GRB 110715A: Swift detection of a bright burst with an optical counterpart
  82. Swift trigger 457076 is not a GRB
  83. Swift Trigger 457076: a possible GRB
  84. GRB 110709B: GROND Detection of an Afterglow Candidate
  85. GRB 110709B: Swift detection of a burst
  86. GRB 110709A: Swift detection of a burst
  87. GRB 110708A: Swift/XRT afterglow candidate for the INTEGRAL burst
  88. Swift-BAT trigger 456532 is not astrophysical
  89. SGR 1E 1841-045: Swift detection of a soft gamma repeater burst
  90. GRB 110625A: Swift detection of a burst
  91. Swift J185003.2-005627: Swift-XRT/UVOT refined analysis
  92. Swift J185003.2-005627: Swift detection of a burst from a new Galactic transient
  93. GRB 110618A: SMARTS optical observations
  94. GRB 110604A: final update on Swift-XRT observations
  95. SGR 1E 1841-045: Swift detection of a soft gamma repeater burst
  96. GRB 110529A: Suzaku WAM observation of the prompt emission
  97. GRB 110530A: Swift detection of a burst with an optical afterglow
  98. GRB 110520A: NOT optical follow-ups
  99. GRB 110521A: Swift detection of a burst
  100. GRB 110520A: Swift detection of a burst

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