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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"

36124 results found.

  1. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  2. GRB 041218: Optical observations
  3. GRB 041219 : optical follow-up observations
  4. Deep RAPTOR observations during GRB 041219
  5. GRB 041218 Optical Observations
  6. GRB 041219 Optical Observations
  7. GRB041219c: Third Burst in One Day from Swift-BAT
  8. GRB041219: Optical Afterglow Detection
  9. GRB041219: Continued NIR Observations
  10. GRB 041219 ,optical observation
  11. GRB 041219: Radio Afterglow Detection
  12. GRB 041218 : Radio Observations
  13. GRB 041218: R-band optical observations
  14. GRB041219: Confirmed NIR Afterglow
  15. GRB041218: Continued P60 Optical Observations
  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: P60 Optical Observations
  34. GRB041217: Infrared Observations
  35. GRB041217: The First GRB Located On-Board Swift
  36. GRB041211: Faulkes Telescope continued optical monitoring
  37. Optical Transient in Lynx not a GRB
  38. Optical transient (GRB?) in Lynx
  39. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  40. GRB041211: Continued P60 Observations
  41. GRB041211: RAPTOR observations
  42. GRB041211: Ashra Prototype optical observation
  43. GRB041211, Faulkes Telescope optical observation
  44. GRB041211, BVRcIc field calibration
  45. GRB 041211: Infrared Observations
  46. GRB 041211: KAIT observations
  47. GRB 041211: Optical follow-up in East Asian region
  48. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  49. GRB041211: P60 optical imaging
  50. GRB970815: Discovery of Optical Afterglow
  51. Distribution of IBAS Alerts for NON-GRB sources
  52. Triangulation of short GRB 041116 (large error box)
  53. GRB 040924: Afterglow Color
  54. GRB 041006: GETS Optical Afterglow Observation
  55. Summary of the recent bursts from SGR 1806-20
  56. GRB 041006: Optical Observations
  57. GRB041006, late-time optical photometry
  58. IBAS GRB Alert # 2034
  59. GRB041006: RTT150 Optical Observations
  60. Bright bursts from SGR1806-20
  61. GRB 041016: BOOTES-2 simultaneous observation
  62. GRB041006: RTT150 Optical Observations
  63. GRB 041016: Optical limits
  64. GRB 041016: Optical limits in V, R, I
  65. GRB 041016:Optical limit during first minute
  66. GRB041016: MASTER: Optical observations
  67. GRB 041015: Optical Observations at Rikubetsu
  68. GRB041006: Near Infrared observations
  69. GRB 041016: Optical limit
  70. GRB 041015 R band observations
  71. GRB040924, BVRcIc field calibration
  72. GRB041015: MASTER: Optical observations
  73. GRB041015,optical observation
  74. GRB 041015: Optical limit at Osaka University
  75. GRB041015 : Optical follow-up at Kiso
  76. GRB 041015 - A long GRB detected by INTEGRAL
  77. GRB 041006 R observations in Loiano
  78. GRB041006: VLT observations of the afterglow and host galaxy
  79. GRB041006: Optical observations and Potential host galaxy
  80. GRB041006, BVRcIc field calibration
  81. GRB 040924: VLT spectroscopy
  82. GRB 041006: SARA afterglow observations
  83. Search for SN light in XRF 040912 with MEGACAM
  84. GRB 040916: Afterglow Color at Early Times
  85. GRB 041006 Optical afterglow observations
  86. IBAS GRB Alert # 2010
  87. GRB 041006: BR observations with VATT
  88. GRB 041006: Redshift confirmed
  89. GRB041006: Liverpool Telescope optical observations
  90. GRB 041006: Colour measurement
  91. GRB041006: break in the light curve
  92. GRB 041006: Radio Observations
  93. GRB041006, further submilllimetre observations
  94. GRB 041006 : optical follow-up observation at Lulin Observatory
  95. GRB 041006 : Optical follow-up observation at TAROT
  96. GRB041006: Optical photometry and spectroscopy at TNG
  97. GRB 041006: presice astrometry
  98. GRB041006 (= H3570): Chandra Observations In Progress
  99. GRB 041006 : optical observation at Bisei
  100. GRB041006 (=HETE3570): optical observations

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