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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"

35944 results found.

  1. GRB 041015 - A long GRB detected by INTEGRAL
  2. GRB 041006 R observations in Loiano
  3. GRB041006: VLT observations of the afterglow and host galaxy
  4. GRB041006: Optical observations and Potential host galaxy
  5. GRB041006, BVRcIc field calibration
  6. GRB 040924: VLT spectroscopy
  7. GRB 041006: SARA afterglow observations
  8. Search for SN light in XRF 040912 with MEGACAM
  9. GRB 040916: Afterglow Color at Early Times
  10. GRB 041006 Optical afterglow observations
  11. IBAS GRB Alert # 2010
  12. GRB 041006: BR observations with VATT
  13. GRB 041006: Redshift confirmed
  14. GRB041006: Liverpool Telescope optical observations
  15. GRB 041006: Colour measurement
  16. GRB041006: break in the light curve
  17. GRB 041006: Radio Observations
  18. GRB041006, further submilllimetre observations
  19. GRB 041006 : optical follow-up observation at Lulin Observatory
  20. GRB 041006 : Optical follow-up observation at TAROT
  21. GRB041006: Optical photometry and spectroscopy at TNG
  22. GRB 041006: presice astrometry
  23. GRB041006 (= H3570): Chandra Observations In Progress
  24. GRB 041006 : optical observation at Bisei
  25. GRB041006 (=HETE3570): optical observations
  26. ROTSE-IIIa Observations of GRB 041006
  27. GRB041006, submillimetre observations
  28. GRB041006: MASTER optical observations
  29. GRB 041006: Optical decay
  30. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  31. GRB 041006 : Optical follow-up observation at KISO
  32. GRB 041006: Finding chart
  33. GRB 041006: Optical afterglow candidate
  34. XRF 020903: Observations of the Host Galaxy (authors)
  35. GRB 040924: Second Epoch WSRT Radio Observations
  36. radio observations, GRB 040924
  37. IBAS Alert 1991. Not a real GRB
  38. GRB040929,optical observation
  39. GRB040924,optical observation
  40. GRB040924, RTT150 optical observation
  41. GRB 040924: detection of possible host galaxy by Subaru
  42. GRB040924, RTT150 optical observation
  43. GRB040924: KAIT observations
  44. GRB040924: Afterglow magnitude at t=17.5hr
  45. GRB 040924: WSRT Radio Observations
  46. GRB 040924: NIR finding chart
  47. GRB040924 : Optical candidate observations at Lulin observatory
  48. GRB040924 : Optical candidate observations at Lulin observatory
  49. GRB 040924: Subaru NIR observation
  50. GRB 040924: RTT150 optical observations
  51. GRB 040924, optical follow-up
  52. IPN triangulation of GRB040924 (H3564)
  53. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  54. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  55. XRF040916: continuing decay of OT
  56. TAROT Observations of GRB 040916 (HETE #3558)
  57. XRF040916, optical observations
  58. XRF040916: Optical Transient Candidate by Subaru
  59. GRB040916 optical limits 17 min after GRB
  60. XRF 040912 (=H3557): Spectral and Temporal Properties
  61. XRF040916, Ic observations
  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. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  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 GRB/XRF 040912 = HETE 3557
  73. An intense burst from SGR1806-20
  74. IBAS GRB Alerts 1978-1980
  75. Optical observations of field of GRB040912
  76. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  77. GRB 040827: XMM-Newton data
  78. GRB040903 - A XRF?
  79. GRB040827: analysis of the XMM-Newton observation
  80. GRB 040903 - INTEGRAL data analysis
  81. IBAS Alert 1974. Not a real GRB
  82. Very bright burst detected from SGR 1806-20
  83. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  84. Possible GRB 040903 - further analysis
  85. Possible GRB 040903 detected with INTEGRAL
  86. GRB 040827 - Radio Observations
  87. XMM-Newton Images of GRB 040827
  88. GRB 040827: optical and NIR observations at the VLT
  89. GRB 040827: UKIRT - 2nd epoch K-band imaging
  90. GRB 040827: 2nd epoch of Magellan K-band imaging
  91. GRB 040827: K imaging - no evidence of variability
  92. GRB 040827: Detection of NIR afterglow
  93. GRB 040827: Possible detection of optical afterglow
  94. GRB 040827: RTT150 optical observations
  95. GRB040825A: optical limit before GRB
  96. GRB 040825B: Optical observations
  97. GRB040827 optical observations
  98. GRB 040827 : Planned XMM-Newton observation
  99. GRB 040827 - Refined position
  100. GRB 040827 : peak flux

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