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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"

2708 results found.

  1. GRB 100727A: Swift detection of a burst
  2. GRB 100725B: refined XRT analysis
  3. GRB 100713A: optical observation in Maidanak
  4. GRB 100628A: Keck/LRIS Spectroscopy of Host Galaxy Candidate
  5. GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
  6. GRB 100628A: Swift XRT/UVOT refined analysis
  7. GRB 100615A: Additional Gemini/NIRI observations
  8. GRB 100702A, Swift-BAT refined analysis
  9. GRB 100628A: GROND optical/NIR observations of the host candidate
  10. GRB100625A: GROND confirmation of constant source
  11. GRB100628A: RTT150 optical observations
  12. GRB 100628A: Swift XRT detection of a possible X-ray afterglow
  13. GRB 100628A: INTEGRAL SPI-ACS light curve
  14. GRB 100621A: Swift/UVOT observations
  15. GRB 100514A: Swift/UVOT Observations
  16. Trigger 421695: Swift detection of a possible burst
  17. GRB 100508A: GROND Detection of the optical afterglow
  18. GRB 100508A: Swift detection of a burst
  19. Trigger 421072: Possible Swift detection of a GRB or transient
  20. GRB 100418A: RTT150 optical observations
  21. GRB 100418A: Possible Evidence for a Supernova
  22. Trigger 420256: Swift detection of a possible GRB
  23. GRB100418A: REM possible afterglow detection
  24. GRB 100413A: GMRT observation of radio afterglow
  25. GRB 100418A: Swift detection of a burst with a possible optical afterglow
  26. GRB 100414A: Swift-XRT detection of a possible X-ray afterglow
  27. GRB 100331B: Swift/XRT possible afterglow candidate
  28. GRB 100331B: SuperAGILE Localization of a Long GRB
  29. GRB 100322B or possible Galactic transient detected in ground analysis of BAT data
  30. Possible pulsation period in SGR 1833-0832
  31. GRB 100319A: Swift detection of a burst; possible SGR
  32. GRB 100316D: Possible Supernova
  33. GRB 100316D: Further Gemini observations
  34. GRB 100316 optical candidate from 1.23m CAHA telescope
  35. GRB 100316 optical candidate from 1.23m CAHA telescope
  36. GRB 100316A: Swift-XRT detection
  37. GRB 1000302A : A possible afterglow candidate
  38. GRB 100213A: Swift XRT refined analysis
  39. GRB 100213B: NOT optical observations
  40. GRB 100119A: Swift detection of a burst
  41. GRB100117A: Possible afterglow from NOT observation
  42. GRB 100115A: SARA Astrometry
  43. GRB 100115A: Swift-XRT candidate afterglow
  44. Swift/BAT Detects an Outburst from XTE J1901+014
  45. Swift Trigger 381591 is probably not a burst
  46. GRB 091231: GROND NIR observations
  47. Trigger 381591: Swift detection of a possible burst
  48. Trigger 381434: Swift detection of a possible burst
  49. GRB 091117: Swift-XRT late time observations
  50. Swift trigger 379449 (possible GRB) is not a burst
  51. GRB 091215: Faulkes Telescope North observations
  52. Trigger 379449: Swift detection of a possible burst
  53. GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
  54. GRB 091123: Fermi GBM detection of a very long burst
  55. Swift trigger 377436 (possible GRB 091130A) is not a burst
  56. GRB 091130: Swift detection of a possible burst
  57. GRB 091127: MASTER early optical transient polarimetry
  58. GRB 091117A: Swift/UVOT followup observations
  59. GRB 091117 BAT refined analysis
  60. GRB 091112: Swift detection of a possible burst
  61. GRB 091109A: GROND and VLT observations
  62. GRB 091109B: VLT observations
  63. GRB 091102: Swift/XRT localization
  64. GRB 091018: Skynet/PROMPT Observations of Possible Host Galaxy
  65. GRB 091020: Late TLS detection
  66. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  67. Fwd: GRB 091003: Possible Supernova Component Retraction
  68. GRB 091003: Possible Supernova Component
  69. GRB 091003: Gemini-N redshift of possible host galaxy
  70. GRB 091010: optical afterglow candidate rejection
  71. GRB 091010: Swift-XRT position
  72. GRB 091003: Lick observations and possible SDSS host galaxy
  73. GRB 090831B: Swift detection of a possible burst
  74. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  75. GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening
  76. GRB 090817: aphotometry of USNO-B1.0 341-0096763
  77. GRB 090814B: Swift-XRT detection of a possible afterglow.
  78. GRB 090814A: Swift-BAT refined analysis
  79. GRB 090809: Swift detection of a burst with a possible optical counterpart
  80. GRB 090807: Swift-XRT refined analysis
  81. GRB 090807, Swift-BAT refined analysis
  82. GRB 090727: Liverpool Telescope possible OT candidate
  83. GRB 090726: Swift-XRT position of probable counterpart
  84. GRB 090720: Gemini-North Imaging and Optical Afterglow
  85. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  86. GRB 090621B: MTM-500 optical observations
  87. Possible GRB090705: Swift-XRT observations
  88. GRB 090705: PAIRITEL NIR Observations
  89. GRB 090705: Swift detection of a possible burst
  90. GRB 090404: Deep optical imaging and possible host association (correction)
  91. GRB 090404: Deep optical imaging and possible host association
  92. GRB 090628: Swift detection of a burst
  93. GRB 090621A: Swift-BAT refined analysis
  94. Ignore GCN/Swift-BAT Lightcurve Notices for trigger 353567
  95. GRB 090531: Swift-BAT refined analysis
  96. GRB 090529: Swift-BAT refined analysis
  97. GRB 090516B: Fermi GBM detection
  98. GRB090510: VLT/FORS2 spectroscopic redshift
  99. GRB 090510: Swift/UVOT host galaxy candidates
  100. GRB 090418A: optical observation

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