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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"

27396 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. Bright bursts from SGR1806-20
  13. GRB 041016: BOOTES-2 simultaneous observation
  14. GRB041006: RTT150 Optical Observations
  15. GRB041016,optical observation
  16. GRB 041016: Optical limits
  17. GRB 041016:Optical limit during first minute
  18. GRB 041015: Optical Observations at Rikubetsu
  19. GRB 041016: Optical limit
  20. GRB 041015 R band observations
  21. GRB040924, BVRcIc field calibration
  22. GRB041015,optical observation
  23. GRB041006: Fading X-ray Afterglow Observed with Chandra
  24. GRB 041015 - A long GRB detected by INTEGRAL
  25. GRB041006: VLT observations of the afterglow and host galaxy
  26. GRB041006: Optical observations and Potential host galaxy
  27. GRB041006, BVRcIc field calibration
  28. GRB 040924: VLT spectroscopy
  29. GRB 041006: SARA afterglow observations
  30. GRB041006, optical observation in CrAO
  31. Search for SN light in XRF 040912 with MEGACAM
  32. GRB 041006: BR observations with VATT
  33. GRB 041006: Redshift confirmed
  34. GRB 041006: Radio Observations
  35. GRB 041006 : optical follow-up observation at Lulin Observatory
  36. GRB041006: Optical photometry and spectroscopy at TNG
  37. GRB 041006: presice astrometry
  38. GRB041006, optical I observation
  39. GRB041006 (=HETE3570): optical observations
  40. ROTSE-IIIa Observations of GRB 041006
  41. GRB041006: MASTER optical observations
  42. GRB041006,optical observation
  43. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  44. GRB041006: Fading of optical afterglow candidate
  45. GRB 041006: Optical afterglow candidate
  46. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  47. XRF 020903: Observations of the Host Galaxy
  48. radio observations, GRB 040924
  49. GRB040929,optical observation
  50. GRB040924,optical observation
  51. GRB040924,optical observation
  52. GRB 040924: detection of possible host galaxy by Subaru
  53. GRB040924: KAIT observations
  54. GRB040924 : Optical candidate observations at Lulin observatory
  55. GRB040924 : Optical candidate observations at Lulin observatory
  56. GRB 040924: Subaru NIR observation
  57. XRF 040912: Radio Observations
  58. XRF 040916: Radio Observations
  59. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  60. XRF040916: continuing decay of OT
  61. TAROT Observations of GRB 040916 (HETE #3558)
  62. GRB040912(=H3557): Candidate Optical Afterglow
  63. XRF040916, optical observations
  64. XRF 040912, identification of CXO sources
  65. XRF040912, BVRcIc field calibration
  66. XRF040916, BVRcIc field calibration
  67. GRB040916: Archival optical observations
  68. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  69. GRB040916: Optical observations
  70. GRB040912 (= H3557): Chandra Observations Scheduled
  71. GRB 040912: Optical Observations
  72. GRB/XRF040912,optical observations
  73. GRB 040912, BVRI observations
  74. Optical observations of field of GRB040912
  75. HETE 3557: Optical observations
  76. GRB040903 - A XRF?
  77. GRB040827: analysis of the XMM-Newton observation
  78. GRB040903, REM near-IR observation
  79. Very bright burst detected from SGR 1806-20
  80. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  81. Possible GRB 040903 - further analysis
  82. GRB 040827 - Radio Observations
  83. XMM-Newton Images of GRB 040827
  84. GRB 040827: optical and NIR observations at the VLT
  85. GRB 040827: UKIRT - 2nd epoch K-band imaging
  86. GRB 040827: 2nd epoch of Magellan K-band imaging
  87. GRB 040827: K imaging - no evidence of variability
  88. GRB 040827: Detection of NIR afterglow
  89. GRB040827 XMM-Newton observation
  90. GRB040825A: optical limit before GRB
  91. GRB 040825B: Optical observations
  92. GRB 040827 : Planned XMM-Newton observation
  93. GRB040825B, BVRcIc field photometry
  94. GRB040825A, BVRcIc field photometry
  95. GCN GRB OBSERBATION REPORT
  96. GRB 040825A,optical observations
  97. GRB040825A: optical observations
  98. GRB040825B: optical observations
  99. MASTER: GRB040825b optical observation
  100. GRB 040825: Optical observations

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