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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"

27398 results found.

  1. GRB041211, BVRcIc field calibration
  2. GRB041211,optical observation
  3. GRB 041211: Infrared Observations
  4. GRB 041211: KAIT observations
  5. GRB 041211: Optical follow-up in East Asian region
  6. Triangulation of short GRB 041116 (large error box)
  7. GRB 040924: Afterglow Color
  8. GRB 041006: GETS Optical Afterglow Observation
  9. Summary of the recent bursts from SGR 1806-20
  10. GRB 041006: Optical Observations
  11. GRB041006, late-time optical photometry
  12. GRB041006: RTT150 Optical Observations
  13. HST Observations: XRF 040701 and 040812
  14. Bright bursts from SGR1806-20
  15. GRB 041016: BOOTES-2 simultaneous observation
  16. GRB041006: RTT150 Optical Observations
  17. GRB041016,optical observation
  18. GRB 041016: Optical limits
  19. GRB 041016:Optical limit during first minute
  20. GRB 041015: Optical Observations at Rikubetsu
  21. GRB 041016: Optical limit
  22. GRB 041015 R band observations
  23. GRB040924, BVRcIc field calibration
  24. GRB041015,optical observation
  25. GRB041006: Fading X-ray Afterglow Observed with Chandra
  26. GRB 041015 - A long GRB detected by INTEGRAL
  27. GRB041006: VLT observations of the afterglow and host galaxy
  28. GRB041006: Optical observations and Potential host galaxy
  29. GRB041006, BVRcIc field calibration
  30. GRB 040924: VLT spectroscopy
  31. GRB 041006: SARA afterglow observations
  32. GRB041006, optical observation in CrAO
  33. Search for SN light in XRF 040912 with MEGACAM
  34. GRB 041006: BR observations with VATT
  35. GRB 041006: Redshift confirmed
  36. GRB 041006: Radio Observations
  37. GRB 041006 : optical follow-up observation at Lulin Observatory
  38. GRB041006: Optical photometry and spectroscopy at TNG
  39. GRB 041006: presice astrometry
  40. GRB041006, optical I observation
  41. GRB041006 (=HETE3570): optical observations
  42. ROTSE-IIIa Observations of GRB 041006
  43. GRB041006: MASTER optical observations
  44. GRB041006,optical observation
  45. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  46. GRB041006: Fading of optical afterglow candidate
  47. GRB 041006: Optical afterglow candidate
  48. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  49. XRF 020903: Observations of the Host Galaxy
  50. radio observations, GRB 040924
  51. GRB040929,optical observation
  52. GRB040924,optical observation
  53. GRB040924,optical observation
  54. GRB 040924: detection of possible host galaxy by Subaru
  55. GRB040924: KAIT observations
  56. GRB040924 : Optical candidate observations at Lulin observatory
  57. GRB040924 : Optical candidate observations at Lulin observatory
  58. GRB 040924: Subaru NIR observation
  59. XRF 040912: Radio Observations
  60. XRF 040916: Radio Observations
  61. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  62. XRF040916: continuing decay of OT
  63. TAROT Observations of GRB 040916 (HETE #3558)
  64. GRB040912(=H3557): Candidate Optical Afterglow
  65. XRF040916, optical observations
  66. XRF 040912, identification of CXO sources
  67. XRF040912, BVRcIc field calibration
  68. XRF040916, BVRcIc field calibration
  69. GRB040916: Archival optical observations
  70. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  71. GRB040916: Optical observations
  72. GRB040912 (= H3557): Chandra Observations Scheduled
  73. GRB 040912: Optical Observations
  74. GRB/XRF040912,optical observations
  75. GRB 040912, BVRI observations
  76. Optical observations of field of GRB040912
  77. HETE 3557: Optical observations
  78. GRB040903 - A XRF?
  79. GRB040827: analysis of the XMM-Newton observation
  80. GRB040903, REM near-IR observation
  81. Very bright burst detected from SGR 1806-20
  82. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  83. Possible GRB 040903 - further analysis
  84. GRB 040827 - Radio Observations
  85. XMM-Newton Images of GRB 040827
  86. GRB 040827: optical and NIR observations at the VLT
  87. GRB 040827: UKIRT - 2nd epoch K-band imaging
  88. GRB 040827: 2nd epoch of Magellan K-band imaging
  89. GRB 040827: K imaging - no evidence of variability
  90. GRB 040827: Detection of NIR afterglow
  91. GRB040827 XMM-Newton observation
  92. GRB040825A: optical limit before GRB
  93. GRB 040825B: Optical observations
  94. GRB 040827 : Planned XMM-Newton observation
  95. GRB040825B, BVRcIc field photometry
  96. GRB040825A, BVRcIc field photometry
  97. GCN GRB OBSERBATION REPORT
  98. GRB 040825A,optical observations
  99. GRB040825A: optical observations
  100. GRB040825B: optical observations

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