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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"

36131 results found.

  1. GRB 041006 : optical follow-up observation at Lulin Observatory
  2. GRB 041006 : Optical follow-up observation at TAROT
  3. GRB041006: Optical photometry and spectroscopy at TNG
  4. GRB 041006: presice astrometry
  5. GRB041006 (= H3570): Chandra Observations In Progress
  6. GRB 041006 : optical observation at Bisei
  7. GRB041006 (=HETE3570): optical observations
  8. ROTSE-IIIa Observations of GRB 041006
  9. GRB041006, submillimetre observations
  10. GRB041006: MASTER optical observations
  11. GRB 041006: Optical decay
  12. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  13. GRB 041006 : Optical follow-up observation at KISO
  14. GRB 041006: Finding chart
  15. GRB 041006: Optical afterglow candidate
  16. XRF 020903: Observations of the Host Galaxy (authors)
  17. GRB 040924: Second Epoch WSRT Radio Observations
  18. radio observations, GRB 040924
  19. IBAS Alert 1991. Not a real GRB
  20. GRB040929,optical observation
  21. GRB040924,optical observation
  22. GRB040924, RTT150 optical observation
  23. GRB 040924: detection of possible host galaxy by Subaru
  24. GRB040924, RTT150 optical observation
  25. GRB040924: KAIT observations
  26. GRB040924: Afterglow magnitude at t=17.5hr
  27. GRB 040924: WSRT Radio Observations
  28. GRB 040924: NIR finding chart
  29. GRB040924 : Optical candidate observations at Lulin observatory
  30. GRB040924 : Optical candidate observations at Lulin observatory
  31. GRB 040924: Subaru NIR observation
  32. GRB 040924: RTT150 optical observations
  33. GRB 040924, optical follow-up
  34. IPN triangulation of GRB040924 (H3564)
  35. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  36. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  37. XRF040916: continuing decay of OT
  38. TAROT Observations of GRB 040916 (HETE #3558)
  39. XRF040916, optical observations
  40. XRF040916: Optical Transient Candidate by Subaru
  41. GRB040916 optical limits 17 min after GRB
  42. XRF 040912 (=H3557): Spectral and Temporal Properties
  43. XRF040916, Ic observations
  44. XRF040912, BVRcIc field calibration
  45. XRF040916, BVRcIc field calibration
  46. GRB040916: Archival optical observations
  47. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  48. GRB040916: Optical observations
  49. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  50. GRB040912 (= H3557): Chandra Observations Scheduled
  51. GRB 040912: Optical Observations
  52. GRB/XRF040912,optical observations
  53. GRB 040912, BVRI observations
  54. Optical observations of GRB/XRF 040912 = HETE 3557
  55. An intense burst from SGR1806-20
  56. IBAS GRB Alerts 1978-1980
  57. Optical observations of field of GRB040912
  58. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  59. GRB 040827: XMM-Newton data
  60. GRB040903 - A XRF?
  61. GRB040827: analysis of the XMM-Newton observation
  62. GRB 040903 - INTEGRAL data analysis
  63. IBAS Alert 1974. Not a real GRB
  64. Very bright burst detected from SGR 1806-20
  65. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  66. Possible GRB 040903 - further analysis
  67. Possible GRB 040903 detected with INTEGRAL
  68. GRB 040827 - Radio Observations
  69. XMM-Newton Images of GRB 040827
  70. GRB 040827: optical and NIR observations at the VLT
  71. GRB 040827: UKIRT - 2nd epoch K-band imaging
  72. GRB 040827: 2nd epoch of Magellan K-band imaging
  73. GRB 040827: K imaging - no evidence of variability
  74. GRB 040827: Detection of NIR afterglow
  75. GRB 040827: Possible detection of optical afterglow
  76. GRB 040827: RTT150 optical observations
  77. GRB040825A: optical limit before GRB
  78. GRB 040825B: Optical observations
  79. GRB040827 optical observations
  80. GRB 040827 : Planned XMM-Newton observation
  81. GRB 040827 - Refined position
  82. GRB 040827 : peak flux
  83. GRB 040827 - A long GRB detected by INTEGRAL
  84. GRB040825B, BVRcIc field photometry
  85. GRB040825A, BVRcIc field photometry
  86. GCN GRB OBSERBATION REPORT
  87. GRB 040825A,optical observations
  88. Increase of SGR 1806-20 activity
  89. GRB 040825A: Optical observations.
  90. GRB040825B: Correction to GCN 2657
  91. GRB 040825: Optical observations
  92. GRB 040812: Second epoch CXO Observations
  93. GRB040823,optical observation
  94. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  95. XRF 040812: optical observation at VLT
  96. GRB 040812: Optical counterparts of CXO sources
  97. XRF040812: possible afterglow
  98. CXO observation of GRB 040812
  99. IPN/HETE localizations of GRB040810 (=H3489)
  100. GRB 040812: Keck and LCO optical observations

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