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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"

27393 results found.

  1. Triangulation of short GRB 041116 (large error box)
  2. GRB 040924: Afterglow Color
  3. GRB 041006: GETS Optical Afterglow Observation
  4. Summary of the recent bursts from SGR 1806-20
  5. GRB 041006: Optical Observations
  6. GRB041006, late-time optical photometry
  7. GRB041006: RTT150 Optical Observations
  8. HST Observations: XRF 040701 and 040812
  9. Bright bursts from SGR1806-20
  10. GRB 041016: BOOTES-2 simultaneous observation
  11. GRB041006: RTT150 Optical Observations
  12. GRB041016,optical observation
  13. GRB 041016: Optical limits
  14. GRB 041016:Optical limit during first minute
  15. GRB 041015: Optical Observations at Rikubetsu
  16. GRB 041016: Optical limit
  17. GRB 041015 R band observations
  18. GRB040924, BVRcIc field calibration
  19. GRB041015,optical observation
  20. GRB041006: Fading X-ray Afterglow Observed with Chandra
  21. GRB 041015 - A long GRB detected by INTEGRAL
  22. GRB041006: VLT observations of the afterglow and host galaxy
  23. GRB041006: Optical observations and Potential host galaxy
  24. GRB041006, BVRcIc field calibration
  25. GRB 040924: VLT spectroscopy
  26. GRB 041006: SARA afterglow observations
  27. GRB041006, optical observation in CrAO
  28. Search for SN light in XRF 040912 with MEGACAM
  29. GRB 041006: BR observations with VATT
  30. GRB 041006: Redshift confirmed
  31. GRB 041006: Radio Observations
  32. GRB 041006 : optical follow-up observation at Lulin Observatory
  33. GRB041006: Optical photometry and spectroscopy at TNG
  34. GRB 041006: presice astrometry
  35. GRB041006, optical I observation
  36. GRB041006 (=HETE3570): optical observations
  37. ROTSE-IIIa Observations of GRB 041006
  38. GRB041006: MASTER optical observations
  39. GRB041006,optical observation
  40. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  41. GRB041006: Fading of optical afterglow candidate
  42. GRB 041006: Optical afterglow candidate
  43. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  44. XRF 020903: Observations of the Host Galaxy
  45. radio observations, GRB 040924
  46. GRB040929,optical observation
  47. GRB040924,optical observation
  48. GRB040924,optical observation
  49. GRB 040924: detection of possible host galaxy by Subaru
  50. GRB040924: KAIT observations
  51. GRB040924 : Optical candidate observations at Lulin observatory
  52. GRB040924 : Optical candidate observations at Lulin observatory
  53. GRB 040924: Subaru NIR observation
  54. XRF 040912: Radio Observations
  55. XRF 040916: Radio Observations
  56. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  57. XRF040916: continuing decay of OT
  58. TAROT Observations of GRB 040916 (HETE #3558)
  59. GRB040912(=H3557): Candidate Optical Afterglow
  60. XRF040916, optical observations
  61. XRF 040912, identification of CXO sources
  62. XRF040912, BVRcIc field calibration
  63. XRF040916, BVRcIc field calibration
  64. GRB040916: Archival optical observations
  65. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  66. GRB040916: Optical observations
  67. GRB040912 (= H3557): Chandra Observations Scheduled
  68. GRB 040912: Optical Observations
  69. GRB/XRF040912,optical observations
  70. GRB 040912, BVRI observations
  71. Optical observations of field of GRB040912
  72. HETE 3557: Optical observations
  73. GRB040903 - A XRF?
  74. GRB040827: analysis of the XMM-Newton observation
  75. GRB040903, REM near-IR observation
  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. GRB 040827: UKIRT - 2nd epoch K-band imaging
  83. GRB 040827: 2nd epoch of Magellan K-band imaging
  84. GRB 040827: K imaging - no evidence of variability
  85. GRB 040827: Detection of NIR afterglow
  86. GRB040827 XMM-Newton observation
  87. GRB040825A: optical limit before GRB
  88. GRB 040825B: Optical observations
  89. GRB 040827 : Planned XMM-Newton observation
  90. GRB040825B, BVRcIc field photometry
  91. GRB040825A, BVRcIc field photometry
  92. GCN GRB OBSERBATION REPORT
  93. GRB 040825A,optical observations
  94. GRB040825A: optical observations
  95. GRB040825B: optical observations
  96. MASTER: GRB040825b optical observation
  97. GRB 040825: Optical observations
  98. XRF040812: possible afterglow second Chandra observation
  99. GRB 040812: Second epoch CXO Observations
  100. GRB040823,optical observation

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