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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"

5391 results found.

  1. GRB 131002A: Faulkes Telescope North optical afterglow
  2. GRB 130930A: Swift detection of a burst
  3. Fermi LAT Upper Limits on GRB 130925A
  4. Observation of possible GRB/TDE 130925A by INTEGRAL/SPI-ACS: three activity episodes
  5. GRB 130925A: Historical non-detection from Rosat-HRI
  6. Fermi GBM detection of GRB 130925A and a possible precursor
  7. GRB 130925A: MAXI/GSC detection
  8. GRB 130925A: Swift detection of a burst
  9. GRB 130831A: RTT150 optical observations
  10. GRB 130903A: optical observations
  11. GRB 130912A: AAO optical upper limit
  12. GRB 130606A: Chandra observation
  13. GRB 130912A: GROND observations
  14. GRB 130831A: Maidanak optical observations
  15. GRB 130822A: nearby galaxy redshifts
  16. GRB 130903A: MASTER early optical limit
  17. GRB 130903A: Fermi GBM observation
  18. GRB 130903A: GROND Upper Limits
  19. GRB 130816A: Swift/UVOT Upper Limits
  20. GRB 130807A: Swift-XRT refined analysis
  21. GRB 130807A, Swift-BAT refined analysis
  22. GRB 130803A; Fermi GBM observation
  23. GRB 130727A: Faulkes Telescope South optical afterglow
  24. GRB 130727A: Swift-XRT and Swift-UVOT prompt observations
  25. GRB 130719A: Swift detection of a burst
  26. GRB 130716A: Probable short-hard burst with delayed Swift data
  27. GRB 130708A: Swift XRT and UVOT Observations
  28. GRB 130702A: NOT optical observations
  29. GRB 130702A / Fermi394416326 : Nanshan optical observations
  30. Fermi394416326: FTN detection
  31. Fermi394416326: iPTF detection of a possible optical afterglow
  32. GRB 130627A: Swift detection of a burst
  33. GRB 130626A: Swift detection of a short burst
  34. Swift Trigger 558828 is not an interesting event
  35. GRB 130610A: CrAO optical observations
  36. GRB 130612A: Fermi GBM observation
  37. GRB 130612A: Swift detection of a burst with an optical counterpart
  38. GRB 130610A: ISON-NM optical observations
  39. GRB 130610A: Fermi GBM Observation
  40. GRB 130609B: Swift/UVOT Observations
  41. GRB 130610A: Skynet/PROMPT detection of the optical afterglow
  42. GRB 130610A: Swift detection of a burst with an optical counterpart
  43. GRB 130609B: Swift detection of a burst with an optical counterpart
  44. GRB 130609A: Fermi GBM observation
  45. GRB 130609A: P60 nondetection
  46. GRB 130609A: Swift detection of a burst
  47. Swift Trigger 557674 was due to an onboard position error
  48. GRB 130603A: AAO optical observations
  49. GRB 130606A: GROND Detection of the Optical/NIR Afterglow
  50. GRB 130606A: LOAO IZY Observation
  51. GRB 130603B: MASTER-Net early observations and optical sloap limit
  52. GRB 130603A: MITSuME Akeno Optical observation
  53. GRB 130603A: SON optical observations
  54. GRB 130603B: Swift-BAT refined analysis
  55. GRB 130603A: MITSuME Okayama Optical Observation
  56. GRB 130527A: NOT optical counterpart
  57. Swift Trigger 556533 is probably not an astrophysical event
  58. IPN Triangulation of GRB 130521B
  59. GRB 130518A: Fermi GBM detection
  60. GRB 130515A: FORS2 spectroscopy of candidate counterpart
  61. GRB 130511A: SSO 2.3m observation
  62. GRB 130427A: Amateur observations from Sweden
  63. Refined IPN Triangulation of GRB 130502B
  64. GRB 130504C: further Swift-XRT observations
  65. GRB 130504C: Swift-XRT observations
  66. IPN Triangulation of GRB 130504B
  67. GRB 130502B: possible TNG counterpart
  68. GRB 130502B: P60 Observations
  69. GRB 130502B Swift-XRT observations
  70. GRB 130427A: Fermi GBM observation
  71. GRB 130420A: Redshift from 10.4m GTC
  72. Swift Trigger 554135 is probably not a GRB or transient
  73. GRB 130418A: SMARTS optical/IR afterglow observations
  74. GRB 130418A: LOAO Observation
  75. GRB 130418A: CARMA 3mm detection
  76. GRB 130418A: Swift detection of a burst with an optical counterpart
  77. GRB 130408A: SMARTS optical/IR afterglow observations
  78. GRB 130211A: Retraction of afterglow candidate
  79. GRB 130327A: RATIR Optical/NIR afterglow confirmation
  80. GRB 130327A: Weihai optical obsevations
  81. GRB 130327A: ISON-NM optical upper limit
  82. GRB 130327A: RATIR Optical and NIR Observations
  83. GRB130313A: GTC early optical limits
  84. GRB 130305A: PTF P48 optical upper limits
  85. GRB 130313A: NOT optical upper limit
  86. GRB 130313A: Weihai optical upper limit
  87. GRB 130313A: MASTER-Net optical observations
  88. IPN Triangulation of GRB 130307A
  89. Swift XRT observations of GRB 130310A
  90. GRB 130306A: MITSuME Ishigakijima upper limits
  91. IPN triangulation of GRB 130228A
  92. GRB 130305A: Optical Observations
  93. GRB 130307A: Fermi GBM detection
  94. GRB 130306A: MASTER-Net pre-Swift alert observation
  95. GRB 130305A: RATIR Observations
  96. Trigger 549841: Swift detection of SGR1806-20
  97. GRB 130216B: Swift/XRT observations
  98. GRB 130216A: P200 NIR Observations
  99. GRB 130215A: P200 NIR observations
  100. GRB 130215A: GMG optical observation

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