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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"

23410 results found.

  1. GRB 041211: Infrared Observations
  2. GRB 041211: KAIT observations
  3. GRB 041211: Optical follow-up in East Asian region
  4. Triangulation of short GRB 041116 (large error box)
  5. GRB 040924: Afterglow Color
  6. GRB 041006: GETS Optical Afterglow Observation
  7. Summary of the recent bursts from SGR 1806-20
  8. GRB 041006: Optical Observations
  9. GRB041006, late-time optical photometry
  10. GRB041006: RTT150 Optical Observations
  11. HST Observations: XRF 040701 and 040812
  12. GRB 041016: BOOTES-2 simultaneous observation
  13. GRB041006: RTT150 Optical Observations
  14. GRB041016,optical observation
  15. GRB 041016: Optical limits
  16. GRB 041016:Optical limit during first minute
  17. GRB 041016: Optical limit
  18. GRB 041015 R band observations
  19. GRB040924, BVRcIc field calibration
  20. GRB041015,optical observation
  21. GRB041006: Fading X-ray Afterglow Observed with Chandra
  22. GRB 041015 - A long GRB detected by INTEGRAL
  23. GRB041006: Optical observations and Potential host galaxy
  24. GRB041006, BVRcIc field calibration
  25. GRB 041006: SARA afterglow observations
  26. GRB041006, optical observation in CrAO
  27. Search for SN light in XRF 040912 with MEGACAM
  28. GRB 040916: Afterglow Color at Early Times
  29. GRB 041006: BR observations with VATT
  30. GRB 041006 : Optical follow-up observation at TAROT
  31. GRB041006, optical I observation
  32. GRB041006 (=HETE3570): optical observations
  33. ROTSE-IIIa Observations of GRB 041006
  34. GRB041006: MASTER optical observations
  35. GRB041006,optical observation
  36. GRB041006: Fading of optical afterglow candidate
  37. GRB 041006: Optical afterglow candidate
  38. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  39. XRF 020903: Observations of the Host Galaxy
  40. radio observations, GRB 040924
  41. GRB040929,optical observation
  42. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  43. GRB040924,optical observation
  44. GRB040924,optical observation
  45. GRB040924: KAIT observations
  46. GRB 040924: WSRT Radio Observations
  47. GRB 040924: Subaru NIR observation
  48. GRB 040924, optical follow-up
  49. IPN triangulation of GRB040924 (H3564)
  50. XRF 040912: Radio Observations
  51. XRF 040916: Radio Observations
  52. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  53. XRF040916: continuing decay of OT
  54. TAROT Observations of GRB 040916 (HETE #3558)
  55. GRB040912(=H3557): Candidate Optical Afterglow
  56. XRF040916, optical observations
  57. XRF 040912, identification of CXO sources
  58. XRF040916, Ic observations
  59. XRF040912, BVRcIc field calibration
  60. XRF040916, BVRcIc field calibration
  61. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  62. GRB040916: Optical observations
  63. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  64. GRB 040912: Optical Observations
  65. GRB/XRF040912,optical observations
  66. GRB 040912, BVRI observations
  67. Optical observations of GRB/XRF 040912 = HETE 3557
  68. An intense burst from SGR1806-20
  69. GRB040912 : Kiso Optical follow-up observation
  70. Optical observations of field of GRB040912
  71. HETE 3557: Optical observations
  72. GRB040903 - A XRF?
  73. GRB040827: analysis of the XMM-Newton observation
  74. GRB040903, REM near-IR observation
  75. GRB 040903 - INTEGRAL data analysis
  76. Very bright burst detected from SGR 1806-20
  77. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  78. Possible GRB 040903 - further analysis
  79. GRB 040827 - Radio Observations
  80. XMM-Newton Images of GRB 040827
  81. GRB 040827: optical and NIR observations at the VLT
  82. GRB040827 XMM-Newton observation
  83. GRB 040825B: Optical observations
  84. GRB 040827 : Planned XMM-Newton observation
  85. GRB 040827 - A long GRB detected by INTEGRAL
  86. GRB040825B, BVRcIc field photometry
  87. GRB040825A, BVRcIc field photometry
  88. GCN GRB OBSERBATION REPORT
  89. GRB 040825A,optical observations
  90. Increase of SGR 1806-20 activity
  91. GRB040825A: optical observations
  92. GRB040825B: optical observations
  93. GRB 040825A: Optical observations.
  94. XRF040812: possible afterglow second Chandra observation
  95. GRB 040812: Second epoch CXO Observations
  96. GRB040823,optical observation
  97. XRF040812: GMRT observations
  98. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  99. XRF 040812: optical observation at VLT
  100. GRB 040812: Optical counterparts of CXO sources

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