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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"

36796 results found.

  1. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  2. GRB 041217: PROMPT Observations
  3. GRB041218: optical observations
  4. GRB041217: optical limit 30 min after GRB
  5. GRB 041218; optical candidate
  6. GRB 041218: Optical observations
  7. GRB 041217: LCO40 Optical Observations and Possible Candidates
  8. GRB 041218 - A long GRB detected by integral
  9. GRB041217: Optical Observations
  10. GRB041217: P60 Optical Observations
  11. GRB041217: Infrared Observations
  12. GRB041217: The First GRB Located On-Board Swift
  13. GRB041211: Faulkes Telescope continued optical monitoring
  14. Optical Transient in Lynx not a GRB
  15. Optical transient (GRB?) in Lynx
  16. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  17. GRB041211: Continued P60 Observations
  18. GRB041211: RAPTOR observations
  19. GRB041211: Ashra Prototype optical observation
  20. GRB041211, Faulkes Telescope optical observation
  21. GRB041211, BVRcIc field calibration
  22. GRB 041211: Infrared Observations
  23. GRB 041211: KAIT observations
  24. GRB 041211: Optical follow-up in East Asian region
  25. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  26. GRB041211: P60 optical imaging
  27. GRB970815: Discovery of Optical Afterglow
  28. Distribution of IBAS Alerts for NON-GRB sources
  29. Triangulation of short GRB 041116 (large error box)
  30. GRB 040924: Afterglow Color
  31. GRB 041006: GETS Optical Afterglow Observation
  32. Summary of the recent bursts from SGR 1806-20
  33. GRB 041006: Optical Observations
  34. GRB041006, late-time optical photometry
  35. IBAS GRB Alert # 2034
  36. GRB041006: RTT150 Optical Observations
  37. Bright bursts from SGR1806-20
  38. GRB 041016: BOOTES-2 simultaneous observation
  39. GRB041006: RTT150 Optical Observations
  40. GRB 041016: Optical limits
  41. GRB 041016: Optical limits in V, R, I
  42. GRB 041016:Optical limit during first minute
  43. GRB041016: MASTER: Optical observations
  44. GRB 041015: Optical Observations at Rikubetsu
  45. GRB041006: Near Infrared observations
  46. GRB 041016: Optical limit
  47. GRB 041015 R band observations
  48. GRB040924, BVRcIc field calibration
  49. GRB041015: MASTER: Optical observations
  50. GRB041015,optical observation
  51. GRB 041015: Optical limit at Osaka University
  52. GRB041015 : Optical follow-up at Kiso
  53. GRB 041015 - A long GRB detected by INTEGRAL
  54. GRB 041006 R observations in Loiano
  55. GRB041006: VLT observations of the afterglow and host galaxy
  56. GRB041006: Optical observations and Potential host galaxy
  57. GRB041006, BVRcIc field calibration
  58. GRB 040924: VLT spectroscopy
  59. GRB 041006: SARA afterglow observations
  60. Search for SN light in XRF 040912 with MEGACAM
  61. GRB 040916: Afterglow Color at Early Times
  62. GRB 041006 Optical afterglow observations
  63. IBAS GRB Alert # 2010
  64. GRB 041006: BR observations with VATT
  65. GRB 041006: Redshift confirmed
  66. GRB041006: Liverpool Telescope optical observations
  67. GRB 041006: Colour measurement
  68. GRB041006: break in the light curve
  69. GRB 041006: Radio Observations
  70. GRB041006, further submilllimetre observations
  71. GRB 041006 : optical follow-up observation at Lulin Observatory
  72. GRB 041006 : Optical follow-up observation at TAROT
  73. GRB041006: Optical photometry and spectroscopy at TNG
  74. GRB 041006: presice astrometry
  75. GRB041006 (= H3570): Chandra Observations In Progress
  76. GRB 041006 : optical observation at Bisei
  77. GRB041006 (=HETE3570): optical observations
  78. ROTSE-IIIa Observations of GRB 041006
  79. GRB041006, submillimetre observations
  80. GRB041006: MASTER optical observations
  81. GRB 041006: Optical decay
  82. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  83. GRB 041006 : Optical follow-up observation at KISO
  84. GRB 041006: Finding chart
  85. GRB 041006: Optical afterglow candidate
  86. XRF 020903: Observations of the Host Galaxy (authors)
  87. GRB 040924: Second Epoch WSRT Radio Observations
  88. radio observations, GRB 040924
  89. IBAS Alert 1991. Not a real GRB
  90. GRB040929,optical observation
  91. GRB040924,optical observation
  92. GRB040924, RTT150 optical observation
  93. GRB 040924: detection of possible host galaxy by Subaru
  94. GRB040924, RTT150 optical observation
  95. GRB040924: KAIT observations
  96. GRB040924: Afterglow magnitude at t=17.5hr
  97. GRB 040924: WSRT Radio Observations
  98. GRB 040924: NIR finding chart
  99. GRB040924 : Optical candidate observations at Lulin observatory
  100. GRB040924 : Optical candidate observations at Lulin observatory

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