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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"

36023 results found.

  1. GRB 041006: presice astrometry
  2. GRB041006 (= H3570): Chandra Observations In Progress
  3. GRB 041006 : optical observation at Bisei
  4. GRB041006 (=HETE3570): optical observations
  5. ROTSE-IIIa Observations of GRB 041006
  6. GRB041006, submillimetre observations
  7. GRB041006: MASTER optical observations
  8. GRB 041006: Optical decay
  9. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  10. GRB 041006 : Optical follow-up observation at KISO
  11. GRB 041006: Finding chart
  12. GRB 041006: Optical afterglow candidate
  13. XRF 020903: Observations of the Host Galaxy (authors)
  14. GRB 040924: Second Epoch WSRT Radio Observations
  15. radio observations, GRB 040924
  16. IBAS Alert 1991. Not a real GRB
  17. GRB040929,optical observation
  18. GRB040924,optical observation
  19. GRB040924, RTT150 optical observation
  20. GRB 040924: detection of possible host galaxy by Subaru
  21. GRB040924, RTT150 optical observation
  22. GRB040924: KAIT observations
  23. GRB040924: Afterglow magnitude at t=17.5hr
  24. GRB 040924: WSRT Radio Observations
  25. GRB 040924: NIR finding chart
  26. GRB040924 : Optical candidate observations at Lulin observatory
  27. GRB040924 : Optical candidate observations at Lulin observatory
  28. GRB 040924: Subaru NIR observation
  29. GRB 040924: RTT150 optical observations
  30. GRB 040924, optical follow-up
  31. IPN triangulation of GRB040924 (H3564)
  32. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  33. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  34. XRF040916: continuing decay of OT
  35. TAROT Observations of GRB 040916 (HETE #3558)
  36. XRF040916, optical observations
  37. XRF040916: Optical Transient Candidate by Subaru
  38. GRB040916 optical limits 17 min after GRB
  39. XRF 040912 (=H3557): Spectral and Temporal Properties
  40. XRF040916, Ic observations
  41. XRF040912, BVRcIc field calibration
  42. XRF040916, BVRcIc field calibration
  43. GRB040916: Archival optical observations
  44. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  45. GRB040916: Optical observations
  46. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  47. GRB040912 (= H3557): Chandra Observations Scheduled
  48. GRB 040912: Optical Observations
  49. GRB/XRF040912,optical observations
  50. GRB 040912, BVRI observations
  51. Optical observations of GRB/XRF 040912 = HETE 3557
  52. An intense burst from SGR1806-20
  53. IBAS GRB Alerts 1978-1980
  54. Optical observations of field of GRB040912
  55. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  56. GRB 040827: XMM-Newton data
  57. GRB040903 - A XRF?
  58. GRB040827: analysis of the XMM-Newton observation
  59. GRB 040903 - INTEGRAL data analysis
  60. IBAS Alert 1974. Not a real GRB
  61. Very bright burst detected from SGR 1806-20
  62. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  63. Possible GRB 040903 - further analysis
  64. Possible GRB 040903 detected with INTEGRAL
  65. GRB 040827 - Radio Observations
  66. XMM-Newton Images of GRB 040827
  67. GRB 040827: optical and NIR observations at the VLT
  68. GRB 040827: UKIRT - 2nd epoch K-band imaging
  69. GRB 040827: 2nd epoch of Magellan K-band imaging
  70. GRB 040827: K imaging - no evidence of variability
  71. GRB 040827: Detection of NIR afterglow
  72. GRB 040827: Possible detection of optical afterglow
  73. GRB 040827: RTT150 optical observations
  74. GRB040825A: optical limit before GRB
  75. GRB 040825B: Optical observations
  76. GRB040827 optical observations
  77. GRB 040827 : Planned XMM-Newton observation
  78. GRB 040827 - Refined position
  79. GRB 040827 : peak flux
  80. GRB 040827 - A long GRB detected by INTEGRAL
  81. GRB040825B, BVRcIc field photometry
  82. GRB040825A, BVRcIc field photometry
  83. GCN GRB OBSERBATION REPORT
  84. GRB 040825A,optical observations
  85. Increase of SGR 1806-20 activity
  86. GRB 040825A: Optical observations.
  87. GRB040825B: Correction to GCN 2657
  88. GRB 040825: Optical observations
  89. GRB 040812: Second epoch CXO Observations
  90. GRB040823,optical observation
  91. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  92. XRF 040812: optical observation at VLT
  93. GRB 040812: Optical counterparts of CXO sources
  94. XRF040812: possible afterglow
  95. CXO observation of GRB 040812
  96. IPN/HETE localizations of GRB040810 (=H3489)
  97. GRB 040812: Keck and LCO optical observations
  98. GRB 040812: Keck and LCO observations
  99. GRB 040812: radio observations
  100. GRB040812, optical/IR observations

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