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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"
  1. GRB 071112C: optical observation
  2. GRB 071112C: optical observation
  3. GRB 071112C: emission lines and refined VLT redshift
  4. GRB 071112C MITSuME Akeno early optical observation
  5. GRB 071112C: Gemini Absorption Redshift
  6. GRB 071112B: 2nd epoch of Magellan i-band imaging
  7. GRB 071112C: SARA upper limit
  8. GRB 071112C : Second Epoch Lulin R-band observations
  9. GRB071112C MITSuME Okayama Optical Observation
  10. GRB 071112C: Swift-BAT refined analysis
  11. GRB 071112C: Swift/UVOT observations
  12. GRB 071112C: Swift XRT refined analysis
  13. GRB 071112C: Optical observations at Crni Vrh
  14. Swift UVOT upper limits of GRB071112B
  15. GRB 071112C: VLT redshift
  16. GRB 071112B: Magellan i-band imaging
  17. GRB 071112B: Gemini Optical Imaging (Correction)
  18. GRB 071112B: Gemini Optical Imaging
  19. GRB 071112B: Swift-XRT preliminary analysis
  20. GRB 071112B, Swift-BAT partial refined analysis of the SHB
  21. GRB071112C: NOT observations
  22. GRB 071112C: Palomar Pre-Imaging
  23. Swift-BAT trigger 296491 is not a GRB
  24. GRB 071112C : Lulin R-band observation
  25. GRB 071112C: RTT150 optical observations
  26. GRB 071112C: TAROT Calern observatory optical observations
  27. Swift XRT follow-up observations of GRB071028B
  28. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  29. GRB 071112C: Optical and NIR afterglows observed with KANATA
  30. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  31. GRB 071112B: ROTSE-III Rapid Optical Limits
  32. GRB 071112C: Swift detection of a burst with an optical counterpart
  33. GRB 071112B: Swift detection of a short hard burst
  34. GRB 071112: Swift detection of a possible burst
  35. GRB071109: Super-LOTIS observations
  36. VLA IInd observation of INTEGRAL burst GRB 071109
  37. Swift/UVOT initial analysis of GRB071109
  38. GRB 071109: further Swift-XRT analysis
  39. GRB 071109: TAROT Calern observatory optical observations
  40. No radio detection at Swift-XRT position
  41. GRB 071109: Swift-XRT possible X-ray counterpart
  42. VLA prompt radio detection of the INTEGRAL burst 071109
  43. GRB 071109: IBIS refined analysis
  44. GRB 071109: BOOTES-2 prompt optical observations
  45. GRB 071109: A long GRB detected by INTEGRAL
  46. GRB 071104: Swift-XRT Team Refined Analysis
  47. GRB 071104: Possible Swift UVOT Afterglow Candidate
  48. GRB 071104: Swift-XRT position
  49. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  50. GRB071010b: optical observation
  51. Swift XRT and UVOT observations of GRB071028B
  52. GRB 071101, Swift-BAT refined analysis
  53. GRB 071101: Swift-XRT Team refined analysis
  54. GRB071101: Optical and NIR upper limits by KANATA
  55. GRB0711101: Two new source from Xinglong TNT observation
  56. GRB 071101: TAROT Calern observatory optical observations
  57. GRB 071101: Swift XRT position
  58. GRB071101 LOAO B,V,R,I observation
  59. GRB 071101: BOOTES-2 prompt optical observations
  60. GRB 071101: a nearby galaxy
  61. GRB 071101: Swift detection of a burst
  62. GRB 071031, Swift-BAT refined analysis
  63. GRB 071031: Swift/UVOT detection of afterglow
  64. GRB 071031: Swift-XRT Team refined analysis
  65. GRB 071020: MITSuME Akeno optical observations
  66. GRB 071031: REM NIR and Optical observation
  67. GRB 071031, SMARTS afterglow observations
  68. GRB 071031: VLT high-resolution spectroscopy
  69. GRB071031: Rapid PROMPT Detections
  70. GRB 071031: GROND detection in all bands
  71. GRB 071031: Swift detection of a burst with an optical counterpart
  72. GRB 071028B Swift-BAT detection of a burst
  73. GRB071025: Optical+NIR observations
  74. GRB 071028: SARA observations of variable source
  75. Swift UVOT upper limits to GRB071028
  76. GRB071028: Xinglong EST V-band upper limit
  77. GRB 071028: Swift-XRT Team refined analysis
  78. GRB 071028, Swift-BAT refined analysis
  79. GRB 071028: Swift detection of a burst
  80. GRB 071025: Kuiper Telescope Optical Observations
  81. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  82. GRB 071018: Revised BAT position
  83. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  84. GRB071021: MARGE Optical Limits
  85. GRB071020, optical upper limit
  86. GRB 071025: SARA VRI upper limits
  87. GRB 071025 Milagro GeV/TeV Observations
  88. GRB 071025: SQIID JHK photometry
  89. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  90. GRB071025: Optical Pre-imaging from Palomar
  91. Swift UVOT upper limits
  92. GRB071025: Xinglong TNT I-band upper limit
  93. GRB 071025: Swift-XRT Team refined analysis
  94. GRB 060602A: host redshift
  95. GRB 071025, Swift-BAT refined analysis
  96. GRB 071025: Early Super-LOTIS Observations
  97. GRB 071025: R/I-band update
  98. GRB071021 : CFHT Ks-band observation
  99. GRB 071025: ROTSE-III Refined Analysis
  100. GRB 071025: I-detection, R-dropout?

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