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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"

36134 results found.

  1. GRB041006: break in the light curve
  2. GRB 041006: Radio Observations
  3. GRB041006, further submilllimetre observations
  4. GRB 041006 : optical follow-up observation at Lulin Observatory
  5. GRB 041006 : Optical follow-up observation at TAROT
  6. GRB041006: Optical photometry and spectroscopy at TNG
  7. GRB 041006: presice astrometry
  8. GRB041006 (= H3570): Chandra Observations In Progress
  9. GRB 041006 : optical observation at Bisei
  10. GRB041006 (=HETE3570): optical observations
  11. ROTSE-IIIa Observations of GRB 041006
  12. GRB041006, submillimetre observations
  13. GRB041006: MASTER optical observations
  14. GRB 041006: Optical decay
  15. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  16. GRB 041006 : Optical follow-up observation at KISO
  17. GRB 041006: Finding chart
  18. GRB 041006: Optical afterglow candidate
  19. XRF 020903: Observations of the Host Galaxy (authors)
  20. GRB 040924: Second Epoch WSRT Radio Observations
  21. radio observations, GRB 040924
  22. IBAS Alert 1991. Not a real GRB
  23. GRB040929,optical observation
  24. GRB040924,optical observation
  25. GRB040924, RTT150 optical observation
  26. GRB 040924: detection of possible host galaxy by Subaru
  27. GRB040924, RTT150 optical observation
  28. GRB040924: KAIT observations
  29. GRB040924: Afterglow magnitude at t=17.5hr
  30. GRB 040924: WSRT Radio Observations
  31. GRB 040924: NIR finding chart
  32. GRB040924 : Optical candidate observations at Lulin observatory
  33. GRB040924 : Optical candidate observations at Lulin observatory
  34. GRB 040924: Subaru NIR observation
  35. GRB 040924: RTT150 optical observations
  36. GRB 040924, optical follow-up
  37. IPN triangulation of GRB040924 (H3564)
  38. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  39. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  40. XRF040916: continuing decay of OT
  41. TAROT Observations of GRB 040916 (HETE #3558)
  42. XRF040916, optical observations
  43. XRF040916: Optical Transient Candidate by Subaru
  44. GRB040916 optical limits 17 min after GRB
  45. XRF 040912 (=H3557): Spectral and Temporal Properties
  46. XRF040916, Ic observations
  47. XRF040912, BVRcIc field calibration
  48. XRF040916, BVRcIc field calibration
  49. GRB040916: Archival optical observations
  50. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  51. GRB040916: Optical observations
  52. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  53. GRB040912 (= H3557): Chandra Observations Scheduled
  54. GRB 040912: Optical Observations
  55. GRB/XRF040912,optical observations
  56. GRB 040912, BVRI observations
  57. Optical observations of GRB/XRF 040912 = HETE 3557
  58. An intense burst from SGR1806-20
  59. IBAS GRB Alerts 1978-1980
  60. Optical observations of field of GRB040912
  61. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  62. GRB 040827: XMM-Newton data
  63. GRB040903 - A XRF?
  64. GRB040827: analysis of the XMM-Newton observation
  65. GRB 040903 - INTEGRAL data analysis
  66. IBAS Alert 1974. Not a real GRB
  67. Very bright burst detected from SGR 1806-20
  68. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  69. Possible GRB 040903 - further analysis
  70. Possible GRB 040903 detected with INTEGRAL
  71. GRB 040827 - Radio Observations
  72. XMM-Newton Images of GRB 040827
  73. GRB 040827: optical and NIR observations at the VLT
  74. GRB 040827: UKIRT - 2nd epoch K-band imaging
  75. GRB 040827: 2nd epoch of Magellan K-band imaging
  76. GRB 040827: K imaging - no evidence of variability
  77. GRB 040827: Detection of NIR afterglow
  78. GRB 040827: Possible detection of optical afterglow
  79. GRB 040827: RTT150 optical observations
  80. GRB040825A: optical limit before GRB
  81. GRB 040825B: Optical observations
  82. GRB040827 optical observations
  83. GRB 040827 : Planned XMM-Newton observation
  84. GRB 040827 - Refined position
  85. GRB 040827 : peak flux
  86. GRB 040827 - A long GRB detected by INTEGRAL
  87. GRB040825B, BVRcIc field photometry
  88. GRB040825A, BVRcIc field photometry
  89. GCN GRB OBSERBATION REPORT
  90. GRB 040825A,optical observations
  91. Increase of SGR 1806-20 activity
  92. GRB 040825A: Optical observations.
  93. GRB040825B: Correction to GCN 2657
  94. GRB 040825: Optical observations
  95. GRB 040812: Second epoch CXO Observations
  96. GRB040823,optical observation
  97. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  98. XRF 040812: optical observation at VLT
  99. GRB 040812: Optical counterparts of CXO sources
  100. XRF040812: possible afterglow

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