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

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