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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"

36135 results found.

  1. GRB 041006: Colour measurement
  2. GRB041006: break in the light curve
  3. GRB 041006: Radio Observations
  4. GRB041006, further submilllimetre observations
  5. GRB 041006 : optical follow-up observation at Lulin Observatory
  6. GRB 041006 : Optical follow-up observation at TAROT
  7. GRB041006: Optical photometry and spectroscopy at TNG
  8. GRB 041006: presice astrometry
  9. GRB041006 (= H3570): Chandra Observations In Progress
  10. GRB 041006 : optical observation at Bisei
  11. GRB041006 (=HETE3570): optical observations
  12. ROTSE-IIIa Observations of GRB 041006
  13. GRB041006, submillimetre observations
  14. GRB041006: MASTER optical observations
  15. GRB 041006: Optical decay
  16. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  17. GRB 041006 : Optical follow-up observation at KISO
  18. GRB 041006: Finding chart
  19. GRB 041006: Optical afterglow candidate
  20. XRF 020903: Observations of the Host Galaxy (authors)
  21. GRB 040924: Second Epoch WSRT Radio Observations
  22. radio observations, GRB 040924
  23. IBAS Alert 1991. Not a real GRB
  24. GRB040929,optical observation
  25. GRB040924,optical observation
  26. GRB040924, RTT150 optical observation
  27. GRB 040924: detection of possible host galaxy by Subaru
  28. GRB040924, RTT150 optical observation
  29. GRB040924: KAIT observations
  30. GRB040924: Afterglow magnitude at t=17.5hr
  31. GRB 040924: WSRT Radio Observations
  32. GRB 040924: NIR finding chart
  33. GRB040924 : Optical candidate observations at Lulin observatory
  34. GRB040924 : Optical candidate observations at Lulin observatory
  35. GRB 040924: Subaru NIR observation
  36. GRB 040924: RTT150 optical observations
  37. GRB 040924, optical follow-up
  38. IPN triangulation of GRB040924 (H3564)
  39. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  40. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  41. XRF040916: continuing decay of OT
  42. TAROT Observations of GRB 040916 (HETE #3558)
  43. XRF040916, optical observations
  44. XRF040916: Optical Transient Candidate by Subaru
  45. GRB040916 optical limits 17 min after GRB
  46. XRF 040912 (=H3557): Spectral and Temporal Properties
  47. XRF040916, Ic observations
  48. XRF040912, BVRcIc field calibration
  49. XRF040916, BVRcIc field calibration
  50. GRB040916: Archival optical observations
  51. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  52. GRB040916: Optical observations
  53. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  54. GRB040912 (= H3557): Chandra Observations Scheduled
  55. GRB 040912: Optical Observations
  56. GRB/XRF040912,optical observations
  57. GRB 040912, BVRI observations
  58. Optical observations of GRB/XRF 040912 = HETE 3557
  59. An intense burst from SGR1806-20
  60. IBAS GRB Alerts 1978-1980
  61. Optical observations of field of GRB040912
  62. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  63. GRB 040827: XMM-Newton data
  64. GRB040903 - A XRF?
  65. GRB040827: analysis of the XMM-Newton observation
  66. GRB 040903 - INTEGRAL data analysis
  67. IBAS Alert 1974. Not a real GRB
  68. Very bright burst detected from SGR 1806-20
  69. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  70. Possible GRB 040903 - further analysis
  71. Possible GRB 040903 detected with INTEGRAL
  72. GRB 040827 - Radio Observations
  73. XMM-Newton Images of GRB 040827
  74. GRB 040827: optical and NIR observations at the VLT
  75. GRB 040827: UKIRT - 2nd epoch K-band imaging
  76. GRB 040827: 2nd epoch of Magellan K-band imaging
  77. GRB 040827: K imaging - no evidence of variability
  78. GRB 040827: Detection of NIR afterglow
  79. GRB 040827: Possible detection of optical afterglow
  80. GRB 040827: RTT150 optical observations
  81. GRB040825A: optical limit before GRB
  82. GRB 040825B: Optical observations
  83. GRB040827 optical observations
  84. GRB 040827 : Planned XMM-Newton observation
  85. GRB 040827 - Refined position
  86. GRB 040827 : peak flux
  87. GRB 040827 - A long GRB detected by INTEGRAL
  88. GRB040825B, BVRcIc field photometry
  89. GRB040825A, BVRcIc field photometry
  90. GCN GRB OBSERBATION REPORT
  91. GRB 040825A,optical observations
  92. Increase of SGR 1806-20 activity
  93. GRB 040825A: Optical observations.
  94. GRB040825B: Correction to GCN 2657
  95. GRB 040825: Optical observations
  96. GRB 040812: Second epoch CXO Observations
  97. GRB040823,optical observation
  98. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  99. XRF 040812: optical observation at VLT
  100. GRB 040812: Optical counterparts of CXO sources

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