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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"

2626 results found.

  1. GRB 100905A: UKIRT zJHK Observation
  2. GRB 100901A: Possible WSRT Radio Detection
  3. Optical observations of GRB 100901A
  4. GRB 100902A: GROND observations; afterglow candidate
  5. GRB 100901A: optical observation at Mt.Terskol
  6. GRB 100816A: 10.4-m GTC redshift confirmation
  7. GRB 100816A: VLT and Gemini-N revised redshift
  8. GRB 100816A : Lulin r'-band observation
  9. GRB 100816A: Swift detection of a possibly short burst with optical afterglow
  10. GRB 100805A: the 4-th epoch of SAO RAS optical observations
  11. GRB 100805A: Swift/UVOT Observations of a Possible Late-Time Brightening
  12. GRB 100805A: Swift-BAT refined analysis
  13. Trigger 430975: Swift detection of a possible burst
  14. GRB 100802A: Swift/UVOT Possible Optical Afterglow
  15. GRB 100802A: Liverpool Telescope observations
  16. GRB 100802A: Possible Swift/UVOT Detection of Optical Afterglow
  17. GRB 100728A, Swift-BAT refined analysis
  18. GRB 100728B: Swift detection of a burst with an optical counterpart
  19. GRB 100727A: Swift detection of a burst
  20. GRB 100725B: refined XRT analysis
  21. GRB 100713A: optical observation in Maidanak
  22. GRB 100628A: Keck/LRIS Spectroscopy of Host Galaxy Candidate
  23. GRB 100628A: Near-IR sources coincident with the possible X-ray afterglow
  24. GRB 100628A: Swift XRT/UVOT refined analysis
  25. GRB 100615A: Additional Gemini/NIRI observations
  26. GRB 100702A, Swift-BAT refined analysis
  27. GRB 100628A: GROND optical/NIR observations of the host candidate
  28. GRB100625A: GROND confirmation of constant source
  29. GRB100628A: RTT150 optical observations
  30. GRB 100628A: Swift XRT detection of a possible X-ray afterglow
  31. GRB 100628A: INTEGRAL SPI-ACS light curve
  32. GRB 100621A: Swift/UVOT observations
  33. GRB 100514A: Swift/UVOT Observations
  34. Trigger 421695: Swift detection of a possible burst
  35. GRB 100508A: GROND Detection of the optical afterglow
  36. GRB 100508A: Swift detection of a burst
  37. Trigger 421072: Possible Swift detection of a GRB or transient
  38. GRB 100418A: RTT150 optical observations
  39. GRB 100418A: Possible Evidence for a Supernova
  40. Trigger 420256: Swift detection of a possible GRB
  41. GRB100418A: REM possible afterglow detection
  42. GRB 100413A: GMRT observation of radio afterglow
  43. GRB 100418A: Swift detection of a burst with a possible optical afterglow
  44. GRB 100414A: Swift-XRT detection of a possible X-ray afterglow
  45. GRB 100331B: Swift/XRT possible afterglow candidate
  46. GRB 100331B: SuperAGILE Localization of a Long GRB
  47. GRB 100322B or possible Galactic transient detected in ground analysis of BAT data
  48. Possible pulsation period in SGR 1833-0832
  49. GRB 100319A: Swift detection of a burst; possible SGR
  50. GRB 100316D: Possible Supernova
  51. GRB 100316D: Further Gemini observations
  52. GRB 100316 optical candidate from 1.23m CAHA telescope
  53. GRB 100316 optical candidate from 1.23m CAHA telescope
  54. GRB 100316A: Swift-XRT detection
  55. GRB 1000302A : A possible afterglow candidate
  56. GRB 100213A: Swift XRT refined analysis
  57. GRB 100213B: NOT optical observations
  58. GRB 100119A: Swift detection of a burst
  59. GRB100117A: Possible afterglow from NOT observation
  60. GRB 100115A: SARA Astrometry
  61. GRB 100115A: Swift-XRT candidate afterglow
  62. Swift/BAT Detects an Outburst from XTE J1901+014
  63. Swift Trigger 381591 is probably not a burst
  64. GRB 091231: GROND NIR observations
  65. Trigger 381591: Swift detection of a possible burst
  66. Trigger 381434: Swift detection of a possible burst
  67. GRB 091117: Swift-XRT late time observations
  68. Swift trigger 379449 (possible GRB) is not a burst
  69. GRB 091215: Faulkes Telescope North observations
  70. Trigger 379449: Swift detection of a possible burst
  71. GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
  72. GRB 091123: Fermi GBM detection of a very long burst
  73. Swift trigger 377436 (possible GRB 091130A) is not a burst
  74. GRB 091130: Swift detection of a possible burst
  75. GRB 091127: MASTER early optical transient polarimetry
  76. GRB 091117A: Swift/UVOT followup observations
  77. GRB 091117 BAT refined analysis
  78. GRB 091112: Swift detection of a possible burst
  79. GRB 091109A: GROND and VLT observations
  80. GRB 091109B: VLT observations
  81. GRB 091102: Swift/XRT localization
  82. GRB 091018: Skynet/PROMPT Observations of Possible Host Galaxy
  83. GRB 091020: Late TLS detection
  84. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  85. Fwd: GRB 091003: Possible Supernova Component Retraction
  86. GRB 091003: Possible Supernova Component
  87. GRB 091003: Gemini-N redshift of possible host galaxy
  88. GRB 091010: optical afterglow candidate rejection
  89. GRB 091010: Swift-XRT position
  90. GRB 091003: Lick observations and possible SDSS host galaxy
  91. GRB 090831B: Swift detection of a possible burst
  92. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  93. GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening
  94. GRB 090817: aphotometry of USNO-B1.0 341-0096763
  95. GRB 090814B: Swift-XRT detection of a possible afterglow.
  96. GRB 090814A: Swift-BAT refined analysis
  97. GRB 090809: Swift detection of a burst with a possible optical counterpart
  98. GRB 090807: Swift-XRT refined analysis
  99. GRB 090807, Swift-BAT refined analysis
  100. GRB 090727: Liverpool Telescope possible OT candidate

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