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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"

17798 results found.

  1. GRB 071018: SARA observations
  2. GRB 071018: Swift-XRT observation
  3. GRB 071017 - Swift XRT observations
  4. GRB 071018: Possible OT from Xinglong TNT observation
  5. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  6. GRB 071018, Swift-BAT refined analysis
  7. GRB 071013: 3rd TLS Epoch - constraints on variability
  8. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  9. GRB 071011: MITSuME Optical Observations
  10. GRB 070920A: deep optical observations at the NOT
  11. GRB 071010B: Keck/LRIS Photometry
  12. GRB 071013: TLS Upper Limit
  13. VLA non-detection of GRB 071011
  14. GRB 071013: Optical observations
  15. GRB 071013: optical observations at NOT
  16. GRB071010B, BVRcIc field calibration
  17. GRB 20071013: Xinglong TNT optical Upper Limit
  18. GRB 071010C Swift-BAT detection of a burst
  19. GRB 071011: Optical Limit after 13.95hrs
  20. GRB 071010B correction to GCN 6892 optical observations
  21. GRB 071011: Swift-XRT refined analysis
  22. VLA non-detection of GRB 071010A
  23. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  24. GRB 071011: Confirmation of P60 optical afterglow
  25. GRB 071010B: Optical Detection
  26. GRB 071011: Kanazawa Optical limits
  27. GRB 071011: P60 Optical Afterglow Candidate
  28. GRB 071011: MARGE Optical Limits
  29. GRB 071010B: Super-LOTIS upper limit
  30. GRB 071010B optical photometry
  31. GRB 071011: XRT afterglow detection
  32. GRB 071011: NAYUTA Optical Observation
  33. GRB 071010A: Continued Keck Imaging
  34. GRB 071010B: Bright OT confirmed with TLS
  35. Optical Observation: GRB 071010
  36. Optical observations: GRB 071010A
  37. GRB071010B: Swift/XRT detection
  38. GRB071008: optical observations
  39. GRB 071010A: Keck/LRIS Photometry
  40. GRB 071010 REM NIR observations
  41. GRB 071010: TAROT La Silla observatory detection of the afterglow
  42. Radio detection of GRB 071003 with the VLA
  43. GRB 071003: Possible rebrightening
  44. GRB 071003 : Lulin R-band observations
  45. GRB 071003: MARGE Observations
  46. GRB 071003: P60 Confirmation of Optical Afterglow
  47. GRB 071001: Swift-XRT Team refined analysis
  48. Faulkes Telescope South observations of GRB 071001
  49. GRB 071001: Swift detection of a burst
  50. VLA observation of GRB 070923
  51. GRB 070911, SMARTS optical/IR afterglow observations
  52. GRB 070925: Gemini South Imaging
  53. GRB 070920B: ROTSE-III Early Optical Limits
  54. GRB 070920B: TAROT La Silla observatory optical observations
  55. GRB 070920B: NOT optical observations
  56. GRB 070920: TAROT Calern observatory optical observations
  57. GRB 070917: P60 Observations
  58. GRB 070917: MITSuME Akeno Ic upper limit
  59. GRB 070917: R band observations
  60. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  61. GRB 070809: The Swift evidence for the SHB nature of this burst
  62. GRB 070913: SMARTS optical/IR observations
  63. GRB 070913: TAROT La Silla observatory optical observations
  64. GRB 070911: PAIRITEL IR Observations
  65. GRB 070911: Swift XRT refined analysis
  66. GRB 070809: Confirmation of optical transient
  67. Candidate Orphan GRB Optical Transient in IC 4779
  68. Las Campanas observations of possible TAROT GRB transient near IC
  69. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  70. GRB 070824 - Combined SuperAGILE/IPN Localization
  71. GRB 070731: Swift/UVOT Upper Limit
  72. GRB 070805: UVOT afterglow candidate retraction
  73. GRB 070810B : Faulkes Telescope South Observations
  74. GRB 070810A: Continued Keck Imaging
  75. GRB 070810B: Keck spectroscopy of possible host galaxies
  76. GRB070810B: Swift/UVOT Upper Limits
  77. GRB 070810B: Xinglong TNT optical Upper Limit
  78. GRB070810B: Optical observations with KANATA
  79. GRB 070809: Swift/UVOT Upper Limits
  80. VLA upper limit on the short hard burst GRB 070729
  81. No radio detection in superAGILE burst 070724B
  82. GRB 070809: Keck Imaging
  83. GRB 070810: enhanced Swift-XRT position
  84. GRB 070810: Swift/UVOT Optical Counterpart
  85. GRB 070808: Swift/UVOT upper limits
  86. GRB 070809: Swift detection of a short burst
  87. GRB 070808 : Faulkes Telescope South Observations
  88. GCN Swift XRT update position notices and enhanced position circulars
  89. GRB 070808: Swift XRT refined analysis
  90. GRB 070808: Xinglong TNT optical Upper Limit
  91. GRB070808: Optical observations with KANATA
  92. GRB070808 - SDSS Pre-Burst Observations
  93. GRB 070808: ROTSE-III Optical Limits
  94. GRB070805 XRT and UVOT afterglow candidate
  95. GRB070612A: Radio upper limit from GMRT
  96. Swift/UVOT observations of GRB070805
  97. UVOT observations of SAXJ1810.8-2609
  98. Swift detection of a outburst from SAX J1810.8-2609
  99. VLA non-detection of GRB 070721B
  100. GRB 070802: REM optical observations

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