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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"

45426 results found.

  1. GRB 041219: Infrared Afterglow Candidate
  2. GRB041218, BVRcIc field calibration
  3. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  4. GRB041219: P60 Optical Observations
  5. GRB 041219 - A long GRB detected by INTEGRAL
  6. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  7. GRB 041217: PROMPT Observations
  8. GRB041218: optical observations
  9. GRB041217: optical limit 30 min after GRB
  10. GRB 041218; optical candidate
  11. GRB 041218: Optical observations
  12. GRB 041217: LCO40 Optical Observations and Possible Candidates
  13. GRB 041218 - A long GRB detected by integral
  14. GRB041217: Optical Observations
  15. GRB041217: NIR and optical observations with REM
  16. GRB041217: P60 Optical Observations
  17. GRB041217: Infrared Observations
  18. GRB041217: The First GRB Located On-Board Swift
  19. GRB041211: Faulkes Telescope continued optical monitoring
  20. Optical Transient in Lynx not a GRB
  21. Optical transient (GRB?) in Lynx
  22. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  23. GRB041211: Continued P60 Observations
  24. GRB041211: RAPTOR observations
  25. GRB041211: Ashra Prototype optical observation
  26. GRB041211, Faulkes Telescope optical observation
  27. GRB041211, BVRcIc field calibration
  28. GRB041211,optical observation
  29. GRB 041211: Infrared Observations
  30. GRB 041211: KAIT observations
  31. GRB 041211: Optical follow-up in East Asian region
  32. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  33. GRB041211: P60 optical imaging
  34. GRB970815: Discovery of Optical Afterglow
  35. Distribution of IBAS Alerts for NON-GRB sources
  36. Triangulation of short GRB 041116 (large error box)
  37. GRB041015: Near-Infrared observations
  38. GRB 040924: Afterglow Color
  39. GRB 041006: GETS Optical Afterglow Observation
  40. Summary of the recent bursts from SGR 1806-20
  41. GRB 041006: Optical Observations
  42. GRB041006, late-time optical photometry
  43. GRB041015, optical observation in CrAO
  44. IBAS GRB Alert # 2034
  45. GRB041006: RTT150 Optical Observations
  46. GRB041015 : Multi epoch optical observations
  47. HST Observations: XRF 040701 and 040812
  48. Bright bursts from SGR1806-20
  49. GRB 041016: BOOTES-2 simultaneous observation
  50. GRB041006: RTT150 Optical Observations
  51. GRB041016,optical observation
  52. GRB 041016: Optical limits
  53. GRB 041016: Optical limits in V, R, I
  54. GRB 041016:Optical limit during first minute
  55. GRB041016: MASTER: Optical observations
  56. GRB 041015: Optical Observations at Rikubetsu
  57. GRB041006: Near Infrared observations
  58. GRB 041016: Optical limit
  59. GRB 041015 R band observations
  60. GRB040924, BVRcIc field calibration
  61. GRB041015: MASTER: Optical observations
  62. GRB041015,optical observation
  63. GRB041006: Fading X-ray Afterglow Observed with Chandra
  64. GRB 041015: Optical limit at Osaka University
  65. GRB041015 : Optical follow-up at Kiso
  66. GRB 041015 - A long GRB detected by INTEGRAL
  67. GRB 041006 R observations in Loiano
  68. GRB041006: VLT observations of the afterglow and host galaxy
  69. GRB041006: Optical observations and Potential host galaxy
  70. GRB041006, BVRcIc field calibration
  71. GRB 040924: VLT spectroscopy
  72. GRB 041006: SARA afterglow observations
  73. GRB041006, optical observation in CrAO
  74. Search for SN light in XRF 040912 with MEGACAM
  75. GRB 040916: Afterglow Color at Early Times
  76. GRB 041006 Optical afterglow observations
  77. IBAS GRB Alert # 2010
  78. GRB 041006: BR observations with VATT
  79. GRB 041006: Redshift confirmed
  80. GRB041006: Liverpool Telescope optical observations
  81. GRB 041006: Colour measurement
  82. GRB041006: break in the light curve
  83. GRB 041006: Radio Observations
  84. GRB041006, further submilllimetre observations
  85. GRB 041006 : optical follow-up observation at Lulin Observatory
  86. GRB 041006 : Optical follow-up observation at TAROT
  87. GRB041006: Optical photometry and spectroscopy at TNG
  88. GRB 041006: presice astrometry
  89. GRB041006 (= H3570): Chandra Observations In Progress
  90. GRB 041006 : optical observation at Bisei
  91. GRB041006, optical I observation
  92. GRB041006 (=HETE3570): optical observations
  93. ROTSE-IIIa Observations of GRB 041006
  94. GRB041006, optical observation
  95. GRB041006, submillimetre observations
  96. GRB041006: MASTER optical observations
  97. GRB041006,optical observation
  98. GRB 041006: Optical decay
  99. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  100. Konus-Wind observation of a series SGR 1806-20 bursts on 041005

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