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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 071025 Milagro GeV/TeV Observations
  2. GRB 071025: SQIID JHK photometry
  3. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  4. GRB071025: Optical Pre-imaging from Palomar
  5. Swift UVOT upper limits
  6. GRB071025: Xinglong TNT I-band upper limit
  7. GRB 071025: Swift-XRT Team refined analysis
  8. GRB 060602A: host redshift
  9. GRB 071025, Swift-BAT refined analysis
  10. GRB 071025: Early Super-LOTIS Observations
  11. GRB 071025: R/I-band update
  12. GRB071021 : CFHT Ks-band observation
  13. GRB 071025: ROTSE-III Refined Analysis
  14. GRB 071025: I-detection, R-dropout?
  15. GRB 071025: Swift XRT refined position
  16. GRB 071025a: PAIRITEL observations
  17. GRB071025: REM NIR afterglow
  18. GRB 071025: ROTSE-III Detection of Optical Counterpart
  19. GRB 071025: Swift detection of a burst
  20. GRB 071021: R-band detection and analysis
  21. GRB 071020: BTA spectroscopy
  22. GRB071021: Optical+NIR observations
  23. Possible radio detection of GRB 071021 with the VLA
  24. Optical observations of GRB 071020
  25. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  26. GRB 071020: SARA observations
  27. Radio detection of GRB 071020 with the VLA
  28. GRB071010b: optical observation
  29. GRB 071021: Subaru NIR observation
  30. GRB071021: MITSuME Okayama Optical Upper Limits
  31. GRB 071021: Magellan i-band observation
  32. GRB 071021: Magellan R-band observation
  33. GRB 071021: Z-band detection
  34. GRB 071021: correction to GCNC 6968
  35. GRB 071020: Fading slowly?
  36. GRB 071010B: Fading quickly
  37. GRB 071021: optical and NIR observations
  38. GRB 071021: possible high-z burst
  39. GRB 071021, Swift-BAT refined analysis
  40. GRB071018: 2nd epoch obsevations of Xinglong TNT
  41. GRB 071021: retraction of Faulkes Telescope South candidate
  42. GRB 071021: Swift-XRT Team refined analysis
  43. GRB 071021: Xinglong TNT optical Upper Limit
  44. GRB 071021 : Lulin R-band limit
  45. Konus-Wind observation of GRB 071020
  46. GRB 071021: Faulkes Telescope South optical candidate
  47. GRB 071021: Swift detection of a burst
  48. GRB 071010B: Independent Confirmation of Break
  49. GRB071020A: Xinglong TNT Optical afterglow observations
  50. GRB 071020: Swift-XRT refined analysis
  51. GRB 071020, Swift-BAT refined analysis
  52. GRB 071020A: IR Imaging with PAIRITEL
  53. GRB 071020: VLT spectroscopy
  54. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  55. GRB071020 - SDSS Pre-burst Observations
  56. GRB 071020: Swift detection of a bright burst
  57. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  58. GRB 071018: Mercator Telescope optical observations
  59. Swift autonomous slewing re-enabled
  60. GRB071010b: optical observations
  61. GRB 071018: SARA observations
  62. GRB 071018: Swift-XRT observation
  63. GRB 071017 - Swift XRT observations
  64. VLA radio observation of GRB 071018
  65. GRB071018: Correction to the GCN 6936
  66. GRB071018: Correction to the GCN 6936
  67. GRB071018: Correction to the GCN 6936
  68. GRB071018: Correction to the title of the GCN 6936
  69. GRB 071018: Possible OT from Xinglong TNT observation
  70. GRB 071010B: Light Curve Break Confirmed
  71. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  72. GRB 071018, Swift-BAT refined analysis
  73. GRB 071018?: Swift detection of a possible burst
  74. GRB 071010B: Suzaku WAM observation of the prompt emission
  75. GRB 071013: 3rd TLS Epoch - constraints on variability
  76. GRB 071013: TNT optical data refined analysis
  77. GRB 071010B: Keck/DEIMOS emission-line redshift
  78. GRB 071017: a SHORT GRB detected by INTEGRAL
  79. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  80. GRB071013: optical observations
  81. GRB 071010B: Optical observations of EST
  82. GRB 071010B: TLS 3rd Epoch - finally a break??
  83. GRB 071011: MITSuME Optical Observations
  84. GRB 070920A: deep optical observations at the NOT
  85. GRB 071010B: Photometry after 1.6 days
  86. GRB 071010B: Keck/LRIS Photometry
  87. GRB 071010B: TLS 2nd Epoch, refined analysis
  88. GRB 071013: TLS Upper Limit
  89. Correction to GCN circular no. # 6915 for GRB 071010B
  90. VLA detection of radio afterglow of GRB 071010B
  91. VLA non-detection of GRB 071011
  92. GRB 071013: Optical observations
  93. GRB 071013: optical observations at NOT
  94. GRB 071013, Swift-BAT refined analysis
  95. GRB071013: optical limit
  96. GRB071010B, BVRcIc field calibration
  97. GRB 20071013: Xinglong TNT optical Upper Limit
  98. GRB 071013: Swift detection of a burst
  99. GRB 071010C Swift-BAT detection of a burst
  100. GRB 071011: Optical Limit after 13.95hrs

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