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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"

15556 results found.

  1. Bright X-ray transient / possible XRF in NGC 2770: TNG R imaging
  2. Possible XRF in NGC 2770 - NOT observations of the optical counterpart
  3. Bright X-ray Transient (a XRF? ) in NGC 2770 - A SN optical counterpart?
  4. Bright X-ray Transient in NGC 2770 - A low-luminosity XRF?
  5. GRB 071227: optical afterglow
  6. GRB 071227: Swift-XRT refined analysis
  7. GRB 071227: REM NIR and Optical observations
  8. GRB071020: optical observations
  9. GRB 070429B: Possible UVOT Detection of an Optical Afterglow
  10. GRB 071112C: Optical/NIR observations
  11. GRB071122: Swift/UVOT Observations
  12. GRB 071122: MASTER optical observation
  13. GRB 071122 Swift-XRT refined analysis
  14. GRB071122: Gemini Absorption redshift
  15. GRB 071122: P60 Optical Afterglow Candidate
  16. GRB 071122: ROTSE-III Optical Limits
  17. GRB 071118: P60 Observations
  18. GRB071118 MITSuME OAO optical observation
  19. Swift/UVOT observations of GRB071118
  20. GRB 071117: Swift-XRT revised position
  21. GRB 071117: Gemini Optical Afterglow Discovery
  22. GRB 071117: TAROT La Silla observatory optical observations
  23. GRB 071117: Las Campanas optical observations
  24. GRB 071112C: Optical and NIR data observed with KANATA
  25. GRB 071112C: WSRT Radio Observations
  26. GRB 071112C: optical observation
  27. GRB 071112C: optical observation
  28. GRB 071112C: emission lines and refined VLT redshift
  29. GRB 071112C MITSuME Akeno early optical observation
  30. GRB071112C MITSuME Okayama Optical Observation
  31. GRB 071112C: Optical observations at Crni Vrh
  32. GRB 071112C: VLT redshift
  33. GRB 071112B: Gemini Optical Imaging (Correction)
  34. GRB 071112B: Gemini Optical Imaging
  35. GRB071112C: NOT observations
  36. GRB 071112C : Lulin R-band observation
  37. GRB 071112C: RTT150 optical observations
  38. GRB 071112C: TAROT Calern observatory optical observations
  39. GRB 071112C: Optical and NIR afterglows observed with KANATA
  40. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  41. GRB 071112B: ROTSE-III Rapid Optical Limits
  42. GRB 071112C: Swift detection of a burst with an optical counterpart
  43. GRB 071109: TAROT Calern observatory optical observations
  44. GRB 071109: BOOTES-2 prompt optical observations
  45. GRB071010b: optical observation
  46. Swift XRT and UVOT observations of GRB071028B
  47. GRB071101: Optical and NIR upper limits by KANATA
  48. GRB 071101: TAROT Calern observatory optical observations
  49. GRB 071101: BOOTES-2 prompt optical observations
  50. GRB 071020: MITSuME Akeno optical observations
  51. GRB 071031: REM NIR and Optical observation
  52. GRB 071031, SMARTS afterglow observations
  53. GRB 071031: VLT high-resolution spectroscopy
  54. GRB 071031: Swift detection of a burst with an optical counterpart
  55. GRB071025: Optical+NIR observations
  56. Swift UVOT upper limits to GRB071028
  57. GRB 071025: Kuiper Telescope Optical Observations
  58. GRB 071018: Revised BAT position
  59. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  60. GRB071021: MARGE Optical Limits
  61. GRB071020, optical upper limit
  62. GRB071025: Optical Pre-imaging from Palomar
  63. GRB 071025: Swift-XRT Team refined analysis
  64. GRB 071025: ROTSE-III Refined Analysis
  65. GRB 071025: Swift XRT refined position
  66. GRB 071025: ROTSE-III Detection of Optical Counterpart
  67. GRB 071021: R-band detection and analysis
  68. GRB 071020: BTA spectroscopy
  69. GRB071021: Optical+NIR observations
  70. Optical observations of GRB 071020
  71. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  72. GRB071010b: optical observation
  73. GRB071021: MITSuME Okayama Optical Upper Limits
  74. GRB 071010B: Fading quickly
  75. GRB 071021: optical and NIR observations
  76. GRB 071021: possible high-z burst
  77. GRB071018: 2nd epoch obsevations of Xinglong TNT
  78. GRB 071021: retraction of Faulkes Telescope South candidate
  79. GRB 071021: Swift-XRT Team refined analysis
  80. GRB 071021: Xinglong TNT optical Upper Limit
  81. GRB 071021 : Lulin R-band limit
  82. GRB 071021: Faulkes Telescope South optical candidate
  83. GRB 071010B: Independent Confirmation of Break
  84. GRB071020A: Xinglong TNT Optical afterglow observations
  85. GRB 071020A: IR Imaging with PAIRITEL
  86. GRB 071020: VLT spectroscopy
  87. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  88. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  89. GRB 071018: Mercator Telescope optical observations
  90. GRB071010b: optical observations
  91. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  92. GRB 071013: TNT optical data refined analysis
  93. GRB071013: optical observations
  94. GRB 071010B: Optical observations of EST
  95. GRB 071011: MITSuME Optical Observations
  96. GRB 070920A: deep optical observations at the NOT
  97. GRB 071010B: Keck/LRIS Photometry
  98. GRB 071013: Optical observations
  99. GRB 071013: optical observations at NOT
  100. GRB071013: optical limit

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