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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"

27394 results found.

  1. GRB 041211: Optical follow-up in East Asian region
  2. Triangulation of short GRB 041116 (large error box)
  3. GRB 040924: Afterglow Color
  4. GRB 041006: GETS Optical Afterglow Observation
  5. Summary of the recent bursts from SGR 1806-20
  6. GRB 041006: Optical Observations
  7. GRB041006, late-time optical photometry
  8. GRB041006: RTT150 Optical Observations
  9. HST Observations: XRF 040701 and 040812
  10. Bright bursts from SGR1806-20
  11. GRB 041016: BOOTES-2 simultaneous observation
  12. GRB041006: RTT150 Optical Observations
  13. GRB041016,optical observation
  14. GRB 041016: Optical limits
  15. GRB 041016:Optical limit during first minute
  16. GRB 041015: Optical Observations at Rikubetsu
  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: VLT observations of the afterglow and host galaxy
  24. GRB041006: Optical observations and Potential host galaxy
  25. GRB041006, BVRcIc field calibration
  26. GRB 040924: VLT spectroscopy
  27. GRB 041006: SARA afterglow observations
  28. GRB041006, optical observation in CrAO
  29. Search for SN light in XRF 040912 with MEGACAM
  30. GRB 041006: BR observations with VATT
  31. GRB 041006: Redshift confirmed
  32. GRB 041006: Radio Observations
  33. GRB 041006 : optical follow-up observation at Lulin Observatory
  34. GRB041006: Optical photometry and spectroscopy at TNG
  35. GRB 041006: presice astrometry
  36. GRB041006, optical I observation
  37. GRB041006 (=HETE3570): optical observations
  38. ROTSE-IIIa Observations of GRB 041006
  39. GRB041006: MASTER optical observations
  40. GRB041006,optical observation
  41. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  42. GRB041006: Fading of optical afterglow candidate
  43. GRB 041006: Optical afterglow candidate
  44. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  45. XRF 020903: Observations of the Host Galaxy
  46. radio observations, GRB 040924
  47. GRB040929,optical observation
  48. GRB040924,optical observation
  49. GRB040924,optical observation
  50. GRB 040924: detection of possible host galaxy by Subaru
  51. GRB040924: KAIT observations
  52. GRB040924 : Optical candidate observations at Lulin observatory
  53. GRB040924 : Optical candidate observations at Lulin observatory
  54. GRB 040924: Subaru NIR observation
  55. XRF 040912: Radio Observations
  56. XRF 040916: Radio Observations
  57. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  58. XRF040916: continuing decay of OT
  59. TAROT Observations of GRB 040916 (HETE #3558)
  60. GRB040912(=H3557): Candidate Optical Afterglow
  61. XRF040916, optical observations
  62. XRF 040912, identification of CXO sources
  63. XRF040912, BVRcIc field calibration
  64. XRF040916, BVRcIc field calibration
  65. GRB040916: Archival optical observations
  66. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  67. GRB040916: Optical observations
  68. GRB040912 (= H3557): Chandra Observations Scheduled
  69. GRB 040912: Optical Observations
  70. GRB/XRF040912,optical observations
  71. GRB 040912, BVRI observations
  72. Optical observations of field of GRB040912
  73. HETE 3557: Optical observations
  74. GRB040903 - A XRF?
  75. GRB040827: analysis of the XMM-Newton observation
  76. GRB040903, REM near-IR observation
  77. Very bright burst detected from SGR 1806-20
  78. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  79. Possible GRB 040903 - further analysis
  80. GRB 040827 - Radio Observations
  81. XMM-Newton Images of GRB 040827
  82. GRB 040827: optical and NIR observations at the VLT
  83. GRB 040827: UKIRT - 2nd epoch K-band imaging
  84. GRB 040827: 2nd epoch of Magellan K-band imaging
  85. GRB 040827: K imaging - no evidence of variability
  86. GRB 040827: Detection of NIR afterglow
  87. GRB040827 XMM-Newton observation
  88. GRB040825A: optical limit before GRB
  89. GRB 040825B: Optical observations
  90. GRB 040827 : Planned XMM-Newton observation
  91. GRB040825B, BVRcIc field photometry
  92. GRB040825A, BVRcIc field photometry
  93. GCN GRB OBSERBATION REPORT
  94. GRB 040825A,optical observations
  95. GRB040825A: optical observations
  96. GRB040825B: optical observations
  97. MASTER: GRB040825b optical observation
  98. GRB 040825: Optical observations
  99. XRF040812: possible afterglow second Chandra observation
  100. GRB 040812: Second epoch CXO Observations

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