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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"

26491 results found.

  1. GRB041219: Continued NIR Observations
  2. GRB041219b: A Swift-BAT burst
  3. GRB 041219 ,optical observation
  4. GRB 041219: Radio Afterglow Detection
  5. GRB 041218 : Radio Observations
  6. GRB 041218: R-band optical observations
  7. GRB041218: optical observations
  8. GRB041219: Confirmed NIR Afterglow
  9. GRB041218: Continued P60 Optical Observations
  10. Swift-BAT detection of the bright long burst GRB041219
  11. GRB 041219: Infrared Afterglow Candidate
  12. GRB041219, BVRcIc field calibration
  13. GRB 041219: Infrared Afterglow Candidate
  14. GRB041218, BVRcIc field calibration
  15. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  16. GRB 041219 - A long GRB detected by INTEGRAL
  17. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  18. GRB 041217: PROMPT Observations
  19. GRB041217: optical limit 30 min after GRB
  20. GRB 041217: LCO40 Optical Observations and Possible Candidates
  21. GRB041217: NIR and optical observations with REM
  22. GRB041217: Infrared Observations
  23. GRB041217: The First GRB Located On-Board Swift
  24. GRB041211: Faulkes Telescope continued optical monitoring
  25. Optical transient (GRB?) in Lynx
  26. GRB041211: RAPTOR observations
  27. GRB041211: Ashra Prototype optical observation
  28. GRB041211, Faulkes Telescope optical observation
  29. GRB041211, BVRcIc field calibration
  30. GRB041211,optical observation
  31. GRB 041211: Infrared Observations
  32. GRB 041211: KAIT observations
  33. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  34. GRB970815: Discovery of Optical Afterglow
  35. Triangulation of short GRB 041116 (large error box)
  36. GRB 040924: Afterglow Color
  37. GRB 041006: GETS Optical Afterglow Observation
  38. GRB 041006: Optical Observations
  39. GRB041006, late-time optical photometry
  40. GRB041006: RTT150 Optical Observations
  41. Bright bursts from SGR1806-20
  42. GRB 041016: BOOTES-2 simultaneous observation
  43. GRB041006: RTT150 Optical Observations
  44. GRB041016,optical observation
  45. GRB 041016: Optical limits
  46. GRB 041016:Optical limit during first minute
  47. GRB 041016: Optical limit
  48. GRB 041015 R band observations
  49. GRB040924, BVRcIc field calibration
  50. GRB041015,optical observation
  51. GRB041006: Fading X-ray Afterglow Observed with Chandra
  52. GRB 041006 R observations in Loiano
  53. GRB041006: Optical observations and Potential host galaxy
  54. GRB041006, BVRcIc field calibration
  55. GRB 041006: SARA afterglow observations
  56. GRB041006, optical observation in CrAO
  57. Search for SN light in XRF 040912 with MEGACAM
  58. GRB 040916: Afterglow Color at Early Times
  59. GRB 041006: BR observations with VATT
  60. GRB 041006: Radio Observations
  61. GRB041006: Optical photometry and spectroscopy at TNG
  62. GRB 041006: presice astrometry
  63. GRB041006, optical I observation
  64. GRB041006 (=HETE3570): optical observations
  65. ROTSE-IIIa Observations of GRB 041006
  66. GRB041006: MASTER optical observations
  67. GRB041006,optical observation
  68. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  69. GRB041006: Fading of optical afterglow candidate
  70. GRB 041006: Optical afterglow candidate
  71. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  72. SGR 1806-20 still active
  73. radio observations, GRB 040924
  74. GRB040929,optical observation
  75. GRB040924,optical observation
  76. GRB040924, RTT150 optical observation
  77. GRB040924,optical observation
  78. GRB040924: KAIT observations
  79. GRB 040924: Subaru NIR observation
  80. GRB 040924, optical follow-up
  81. GRB040924 (H3564): Optical afterglow candidate
  82. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  83. XRF040916: continuing decay of OT
  84. TAROT Observations of GRB 040916 (HETE #3558)
  85. GRB040912(=H3557): Candidate Optical Afterglow
  86. XRF040916, optical observations
  87. GRB040916 optical limits 17 min after GRB
  88. XRF 040912, identification of CXO sources
  89. XRF 040912 (=H3557): Spectral and Temporal Properties
  90. XRF040916: optical follow-up observations
  91. XRF040912, BVRcIc field calibration
  92. XRF040916, BVRcIc field calibration
  93. XRF 040916, optical follow-up
  94. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  95. GRB040916: Optical observations
  96. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  97. GRB 040912: Optical Observations
  98. GRB/XRF040912,optical observations
  99. GRB 040912, BVRI observations
  100. Optical observations of GRB/XRF 040912 = HETE 3557

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