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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"

32813 results found.

  1. IBAS Alert 1991. Not a real GRB
  2. GRB040929,optical observation
  3. GRB040924,optical observation
  4. GRB040924, RTT150 optical observation
  5. GRB 040924: detection of possible host galaxy by Subaru
  6. GRB040924, RTT150 optical observation
  7. GRB040924: KAIT observations
  8. GRB040924: Afterglow magnitude at t=17.5hr
  9. GRB 040924: WSRT Radio Observations
  10. GRB 040924: NIR finding chart
  11. GRB040924 : Optical candidate observations at Lulin observatory
  12. GRB040924 : Optical candidate observations at Lulin observatory
  13. GRB 040924: Subaru NIR observation
  14. GRB 040924: RTT150 optical observations
  15. GRB 040924, optical follow-up
  16. IPN triangulation of GRB040924 (H3564)
  17. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  18. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  19. XRF040916: continuing decay of OT
  20. TAROT Observations of GRB 040916 (HETE #3558)
  21. XRF040916, optical observations
  22. XRF040916: Optical Transient Candidate by Subaru
  23. GRB040916 optical limits 17 min after GRB
  24. XRF 040912 (=H3557): Spectral and Temporal Properties
  25. XRF040916, Ic observations
  26. XRF040912, BVRcIc field calibration
  27. XRF040916, BVRcIc field calibration
  28. GRB040916: Archival optical observations
  29. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  30. GRB040916: Optical observations
  31. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  32. GRB040912 (= H3557): Chandra Observations Scheduled
  33. GRB 040912: Optical Observations
  34. GRB/XRF040912,optical observations
  35. GRB 040912, BVRI observations
  36. Optical observations of GRB/XRF 040912 = HETE 3557
  37. An intense burst from SGR1806-20
  38. IBAS GRB Alerts 1978-1980
  39. Optical observations of field of GRB040912
  40. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  41. GRB 040827: XMM-Newton data
  42. GRB040903 - A XRF?
  43. GRB040827: analysis of the XMM-Newton observation
  44. GRB 040903 - INTEGRAL data analysis
  45. IBAS Alert 1974. Not a real GRB
  46. Very bright burst detected from SGR 1806-20
  47. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  48. Possible GRB 040903 - further analysis
  49. Possible GRB 040903 detected with INTEGRAL
  50. GRB 040827 - Radio Observations
  51. XMM-Newton Images of GRB 040827
  52. GRB 040827: optical and NIR observations at the VLT
  53. GRB 040827: UKIRT - 2nd epoch K-band imaging
  54. GRB 040827: 2nd epoch of Magellan K-band imaging
  55. GRB 040827: K imaging - no evidence of variability
  56. GRB 040827: Detection of NIR afterglow
  57. GRB 040827: Possible detection of optical afterglow
  58. GRB 040827: RTT150 optical observations
  59. GRB040825A: optical limit before GRB
  60. GRB 040825B: Optical observations
  61. GRB040827 optical observations
  62. GRB 040827 : Planned XMM-Newton observation
  63. GRB 040827 - Refined position
  64. GRB 040827 : peak flux
  65. GRB 040827 - A long GRB detected by INTEGRAL
  66. GRB040825B, BVRcIc field photometry
  67. GRB040825A, BVRcIc field photometry
  68. GCN GRB OBSERBATION REPORT
  69. GRB 040825A,optical observations
  70. Increase of SGR 1806-20 activity
  71. GRB 040825A: Optical observations.
  72. GRB040825B: Correction to GCN 2657
  73. GRB 040825: Optical observations
  74. GRB 040812: Second epoch CXO Observations
  75. GRB040823,optical observation
  76. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  77. XRF 040812: optical observation at VLT
  78. GRB 040812: Optical counterparts of CXO sources
  79. XRF040812: possible afterglow
  80. CXO observation of GRB 040812
  81. IPN/HETE localizations of GRB040810 (=H3489)
  82. GRB 040812: Keck and LCO optical observations
  83. GRB 040812: Keck and LCO observations
  84. GRB 040812: radio observations
  85. GRB040812, optical/IR observations
  86. Konus-Wind observation of GRB040810 (=H3489)
  87. GRB 040812: a long GRB detected by INTEGRAL
  88. GRB 040810: Optical observations of a limited region
  89. IPN/HETE triangulation of GRB040802 (=H3485)
  90. GRB 040730, infrared observations
  91. GRB 040730: Optical observations
  92. GRB 040730: a long GRB detected with INTEGRAL
  93. Ongoing activity of SGR 1806-20
  94. GRB040624: optical monitoring at TNG
  95. Cancellation of IBAS/INTEGRAL GRB alerts
  96. IBAS Alert 1836: NOT a real GRB
  97. GRB040709 J,H-band observations
  98. GRB 040624: optical observations
  99. GRB 040624: optical observations at TNG and VLT
  100. MASTER: GRB 040624 optical observation after 0,48d

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