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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"

28068 results found.

  1. GRB 071025: SQIID JHK photometry
  2. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  3. Swift UVOT upper limits
  4. GRB071025: Xinglong TNT I-band upper limit
  5. GRB 071025: Swift-XRT Team refined analysis
  6. GRB 071025: Early Super-LOTIS Observations
  7. GRB 071025: R/I-band update
  8. GRB071021 : CFHT Ks-band observation
  9. GRB 071025: ROTSE-III Refined Analysis
  10. GRB 071025: I-detection, R-dropout?
  11. GRB 071025: Swift XRT refined position
  12. GRB071025: REM NIR afterglow
  13. GRB 071025: ROTSE-III Detection of Optical Counterpart
  14. GRB 071025: Swift detection of a burst
  15. GRB 071021: R-band detection and analysis
  16. GRB 071020: BTA spectroscopy
  17. GRB071021: Optical+NIR observations
  18. Possible radio detection of GRB 071021 with the VLA
  19. Optical observations of GRB 071020
  20. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  21. GRB 071020: SARA observations
  22. Radio detection of GRB 071020 with the VLA
  23. GRB071010b: optical observation
  24. GRB 071021: Subaru NIR observation
  25. GRB071021: MITSuME Okayama Optical Upper Limits
  26. GRB 071021: Magellan i-band observation
  27. GRB 071021: Magellan R-band observation
  28. GRB 071021: Z-band detection
  29. GRB 071020: Fading slowly?
  30. GRB 071010B: Fading quickly
  31. GRB 071021: optical and NIR observations
  32. GRB 071021: possible high-z burst
  33. GRB 071021, Swift-BAT refined analysis
  34. GRB071018: 2nd epoch obsevations of Xinglong TNT
  35. GRB 071021: Swift-XRT Team refined analysis
  36. GRB 071021: Xinglong TNT optical Upper Limit
  37. GRB 071021 : Lulin R-band limit
  38. GRB 071021: Faulkes Telescope South optical candidate
  39. GRB 071021: Swift detection of a burst
  40. GRB071020A: Xinglong TNT Optical afterglow observations
  41. GRB 071020: Swift-XRT refined analysis
  42. GRB 071020, Swift-BAT refined analysis
  43. GRB 071020: VLT spectroscopy
  44. GRB 071020: Swift detection of a bright burst
  45. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  46. GRB 071018: Mercator Telescope optical observations
  47. Swift autonomous slewing re-enabled
  48. GRB071010b: optical observations
  49. GRB 071018: SARA observations
  50. GRB 071018: Swift-XRT observation
  51. GRB 071017 - Swift XRT observations
  52. GRB 071010B: Light Curve Break Confirmed
  53. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  54. GRB 071018?: Swift detection of a possible burst
  55. GRB 071013: 3rd TLS Epoch - constraints on variability
  56. GRB 071010B: Keck/DEIMOS emission-line redshift
  57. GRB071013: optical observations
  58. GRB 071010B: Optical observations of EST
  59. GRB 071010B: TLS 3rd Epoch - finally a break??
  60. GRB 071011: MITSuME Optical Observations
  61. GRB 071010B: Keck/LRIS Photometry
  62. GRB 071010B: TLS 2nd Epoch, refined analysis
  63. GRB 071013: TLS Upper Limit
  64. VLA detection of radio afterglow of GRB 071010B
  65. VLA non-detection of GRB 071011
  66. GRB 071013: Optical observations
  67. GRB 071013: optical observations at NOT
  68. GRB 071013: Swift detection of a burst
  69. GRB 071010C Swift-BAT detection of a burst
  70. GRB 071011: Xinglong TNT Optical afterglow observations
  71. GRB 071010B correction to GCN 6892 optical observations
  72. GRB 071011: Swift-XRT refined analysis
  73. VLA non-detection of GRB 071010A
  74. GRB 071011, Optical afterglow
  75. GRB 071011: Confirmation of P60 optical afterglow
  76. GRB 071010B: Optical Detection
  77. GRB 071011: Kanazawa Optical limits
  78. GRB 071011: P60 Optical Afterglow Candidate
  79. GRB 071011: MARGE Optical Limits
  80. GRB 071010B optical photometry
  81. GRB 071011: XRT afterglow detection
  82. GRB 071010B: Keck/LRIS Spectroscopy
  83. GRB 071010B: Gemini Spectroscopic Observations
  84. GRB 071011: Early Super-LOTIS Observations
  85. GRB 071011: NAYUTA Optical Observation
  86. GRB 071010A: Continued Keck Imaging
  87. GRB 071010B: Bright OT confirmed with TLS
  88. GRB 071011: Optical afterglow candidate
  89. GRB 071011: Swift detection of a burst
  90. Optical Observation: GRB 071010
  91. Optical observations: GRB 071010A
  92. GRB071010B: Swift/XRT detection
  93. GRB 071010A: bright NIR afterglow
  94. GRB071008: optical observations
  95. GRB 071010B possible optical transient
  96. GRB 071010A: Keck/LRIS Photometry
  97. GRB 071010B: Swift detection of a burst
  98. GRB 071010: Swift-XRT observation
  99. GRB071008: Swift-XRT observation
  100. GRB 071010 REM NIR observations

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