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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"

45444 results found.

  1. GRB 041218 Optical Observations
  2. GRB 041219 Optical Observations
  3. GRB041219c: Third Burst in One Day from Swift-BAT
  4. GRB041219: Optical Afterglow Detection
  5. GRB041219: Continued NIR Observations
  6. GRB041219b: A Swift-BAT burst
  7. GRB 041219 ,optical observation
  8. GRB 041219: Radio Afterglow Detection
  9. GRB 041218 : Radio Observations
  10. GRB 041218: R-band optical observations
  11. GRB041218: Liverpool Telescope optical observations
  12. GRB041218: optical observations
  13. GRB041219: Confirmed NIR Afterglow
  14. GRB041218: Continued P60 Optical Observations
  15. Swift-BAT detection of the bright long burst GRB041219
  16. GRB 041218: Optical Observation
  17. GRB 041219: Infrared Afterglow Candidate
  18. GRB041219, BVRcIc field calibration
  19. GRB 041219: Infrared Afterglow Candidate
  20. GRB041218, BVRcIc field calibration
  21. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  22. GRB041219: P60 Optical Observations
  23. GRB 041219 - A long GRB detected by INTEGRAL
  24. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  25. GRB 041217: PROMPT Observations
  26. GRB041218: optical observations
  27. GRB041217: optical limit 30 min after GRB
  28. GRB 041218; optical candidate
  29. GRB 041218: Optical observations
  30. GRB 041217: LCO40 Optical Observations and Possible Candidates
  31. GRB 041218 - A long GRB detected by integral
  32. GRB041217: Optical Observations
  33. GRB041217: NIR and optical observations with REM
  34. GRB041217: P60 Optical Observations
  35. GRB041217: Infrared Observations
  36. GRB041217: The First GRB Located On-Board Swift
  37. GRB041211: Faulkes Telescope continued optical monitoring
  38. Optical Transient in Lynx not a GRB
  39. Optical transient (GRB?) in Lynx
  40. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  41. GRB041211: Continued P60 Observations
  42. GRB041211: RAPTOR observations
  43. GRB041211: Ashra Prototype optical observation
  44. GRB041211, Faulkes Telescope optical observation
  45. GRB041211, BVRcIc field calibration
  46. GRB041211,optical observation
  47. GRB 041211: Infrared Observations
  48. GRB 041211: KAIT observations
  49. GRB 041211: Optical follow-up in East Asian region
  50. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  51. GRB041211: P60 optical imaging
  52. GRB970815: Discovery of Optical Afterglow
  53. Distribution of IBAS Alerts for NON-GRB sources
  54. Triangulation of short GRB 041116 (large error box)
  55. GRB041015: Near-Infrared observations
  56. GRB 040924: Afterglow Color
  57. GRB 041006: GETS Optical Afterglow Observation
  58. Summary of the recent bursts from SGR 1806-20
  59. GRB 041006: Optical Observations
  60. GRB041006, late-time optical photometry
  61. GRB041015, optical observation in CrAO
  62. IBAS GRB Alert # 2034
  63. GRB041006: RTT150 Optical Observations
  64. GRB041015 : Multi epoch optical observations
  65. HST Observations: XRF 040701 and 040812
  66. Bright bursts from SGR1806-20
  67. GRB 041016: BOOTES-2 simultaneous observation
  68. GRB041006: RTT150 Optical Observations
  69. GRB041016,optical observation
  70. GRB 041016: Optical limits
  71. GRB 041016: Optical limits in V, R, I
  72. GRB 041016:Optical limit during first minute
  73. GRB041016: MASTER: Optical observations
  74. GRB 041015: Optical Observations at Rikubetsu
  75. GRB041006: Near Infrared observations
  76. GRB 041016: Optical limit
  77. GRB 041015 R band observations
  78. GRB040924, BVRcIc field calibration
  79. GRB041015: MASTER: Optical observations
  80. GRB041015,optical observation
  81. GRB041006: Fading X-ray Afterglow Observed with Chandra
  82. GRB 041015: Optical limit at Osaka University
  83. GRB041015 : Optical follow-up at Kiso
  84. GRB 041015 - A long GRB detected by INTEGRAL
  85. GRB 041006 R observations in Loiano
  86. GRB041006: VLT observations of the afterglow and host galaxy
  87. GRB041006: Optical observations and Potential host galaxy
  88. GRB041006, BVRcIc field calibration
  89. GRB 040924: VLT spectroscopy
  90. GRB 041006: SARA afterglow observations
  91. GRB041006, optical observation in CrAO
  92. Search for SN light in XRF 040912 with MEGACAM
  93. GRB 040916: Afterglow Color at Early Times
  94. GRB 041006 Optical afterglow observations
  95. IBAS GRB Alert # 2010
  96. GRB 041006: BR observations with VATT
  97. GRB 041006: Redshift confirmed
  98. GRB041006: Liverpool Telescope optical observations
  99. GRB 041006: Colour measurement
  100. GRB041006: break in the light curve

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