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

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