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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"

2795 results found.

  1. GRB 090401: Swift detection of a burst
  2. GRB090323: Optical observations from NOT
  3. GRB 090328: Possible Swift/XRT detection
  4. GRB 090323: TLS detection at 5 days, no break
  5. GRB 090320B: MASTER-Net prompt optical observations
  6. GRB 090323 TLS detection - still bright
  7. GRB 090323: Possible XRT Counterpart
  8. GRB 090313: VLT spectroscopy
  9. GRB090305B: MASTER-net prompt optical short burst observations
  10. GRB 090306B: Possible XRT afterglow
  11. GRB 090306: Swift detection of a possible burst
  12. GRB 090303: Fermi GBM detection
  13. GRB 081211B: Nearby cluster
  14. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  15. AXP 1E1547.0-5408: Fermi GBM observations
  16. Trigger 340734: Swift detection of a possible short burst
  17. GRB 090118 (BATSS): GRT Optical Observation
  18. GRB 090118: GROND Upper Limits
  19. GRB 090118: Possible burst detection from Swift-BAT slew data
  20. GRB090117: Swift-XRT detection of a possible candidate afterglow
  21. GRB090113: XRT position
  22. GRB 090112: Fermi GBM detection
  23. GRB 090107B: Swift-XRT detection of possible afterglow
  24. GRB 090107: Swift detection of a burst
  25. GRB 081228, Swift-BAT refined analysis
  26. GRB 081228: Swift-XRT Team refined analysis
  27. GRB 081226: Swift-XRT refined analysis
  28. GRB 081226A: Swift UVOT Upper Limits
  29. GRB 081226: Gemini-South spectrum of possible afterglow
  30. GRB 081226: Swift detection of a possible short-hard burst
  31. GRB 081211B: Further Swift-XRT analysis
  32. Possible GRB 081211B: Swift/UVOT Upper Limits
  33. Possible GRB 081211B - Swift-XRT analysis
  34. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  35. GRB 081211: Swift-BAT refined analysis
  36. GRB 081210: Swift-BAT refined analysis
  37. GRB 081128: optical observation in CrAO
  38. GRB 081204: Swift XRT afterglow candidate
  39. GRB 081203B: Swift-XRT candidate afterglow.
  40. GRB 081130B: MASTER prompt optical observations
  41. GRB 081128: optical observation
  42. GRB 081130B: Fermi GBM detection
  43. GRB 081128A: optical observations
  44. Trigger 335971: Swift possible detection of a burst
  45. GRB081128 : Lulin optical follow-ups
  46. GRB 081128: Swift detection of a burst
  47. GRB 081126: Confirmation of the Optical Afterglow
  48. Fermi GBM detection of a weak source
  49. GRB 081118: optical afterglow candidate
  50. GRB 081109A: confirmation of possible detection host galaxy
  51. GRB 081024B: Swift-XRT late-time observations
  52. Swift-BAT refined analysis of trigger 334129
  53. GRB 081109A: Possible Swift-UVOT detection
  54. GRB 081109A: Faulkes Telescope South observations
  55. GRB 081109A: Swift-XRT refined analysis
  56. Swift-BAT Trigger 334129: possible burst
  57. GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection
  58. GRB 081024B: new Swift-XRT observations
  59. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow (Corrected)
  60. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow
  61. GRB 081025: TLS upper limits
  62. GRB 081024B: Swift-XRT further observations
  63. GRB 081025: Swift-XRT position
  64. GRB 081024B: Swift-XRT observations
  65. GRB 081024: Swift-XRT refined analysis
  66. Swift detection of a possible burst (trigger 332287)
  67. GRB 081011: Swift XRT refined analysis
  68. GRB 081016: Swift-XRT candidate afterglow detection
  69. GRB 081007 and GRB 081007B: Fermi GBM detection
  70. GRB 081003A: Swift-XRT Team position and analysis
  71. Swift discovery of a new Soft Gamma Repeater SGR 1550-5418
  72. GRB080928: Gemini-South Absorption Redshift
  73. Swift detection of a possible GRB (trigger 325707)
  74. GRB 080916C: Swift/XRT detection of possible afterglow
  75. GRB 080916B: Swift UVOT Refined Analysis
  76. GRB 080905B: Refined UVOT Analysis
  77. GRB 080906: Swift detection of a burst with optical afterglow
  78. GRB 080905B: Swift detection of a burst with possible optical counterpart
  79. SGR 0501+4516: preliminary results of the first XMM-Newton observation
  80. SGR 0501+4516: Detection of possible optical counterpart
  81. SGR 0501+4516: WHT observations of the possible near-infrared counterpart
  82. GRB 080828: Swift-XRT detection of a possible X-ray afterglow
  83. Swift trigger 322590: BAT detection of a possible burst
  84. Enhanced Swift-XRT position of SGR 0501+4516
  85. SGR 0501+4516: GMRT Radio Observation at 618 MHz
  86. SGR 0501+4516: Swift XRT measure of the spin period
  87. SGR 0501+4516: Astrotel-Caucasus optical observations
  88. SGR 0501+4516: UKIRT detection of possible infra-red counterpart
  89. GRB 080822 (SGR 0501+4516): archival optical observations
  90. GRB 080810: KANATA optical-NIR observation, update
  91. GRB080804: Gemini South redshift confirmation
  92. GRB 080805: GROND detection of possible afterglow
  93. GRB 080727A: Swift-XRT refined analysis
  94. Retraction of Swift Trigger 317393
  95. Trigger 317393: Swift detection of a possible GRB
  96. GRB 080710: TLS observations, steepening afterglow decay
  97. GRB 080707: possible break in the X-rays
  98. Trigger 315630: Swift detection of a possible burst
  99. GRB 080701: Swift detection of a burst
  100. Swift-BAT trigger 314975 possible burst

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