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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"

36143 results found.

  1. GRB 041006: SARA afterglow observations
  2. Search for SN light in XRF 040912 with MEGACAM
  3. GRB 040916: Afterglow Color at Early Times
  4. GRB 041006 Optical afterglow observations
  5. IBAS GRB Alert # 2010
  6. GRB 041006: BR observations with VATT
  7. GRB 041006: Redshift confirmed
  8. GRB041006: Liverpool Telescope optical observations
  9. GRB 041006: Colour measurement
  10. GRB041006: break in the light curve
  11. GRB 041006: Radio Observations
  12. GRB041006, further submilllimetre observations
  13. GRB 041006 : optical follow-up observation at Lulin Observatory
  14. GRB 041006 : Optical follow-up observation at TAROT
  15. GRB041006: Optical photometry and spectroscopy at TNG
  16. GRB 041006: presice astrometry
  17. GRB041006 (= H3570): Chandra Observations In Progress
  18. GRB 041006 : optical observation at Bisei
  19. GRB041006 (=HETE3570): optical observations
  20. ROTSE-IIIa Observations of GRB 041006
  21. GRB041006, submillimetre observations
  22. GRB041006: MASTER optical observations
  23. GRB 041006: Optical decay
  24. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  25. GRB 041006 : Optical follow-up observation at KISO
  26. GRB 041006: Finding chart
  27. GRB 041006: Optical afterglow candidate
  28. XRF 020903: Observations of the Host Galaxy (authors)
  29. GRB 040924: Second Epoch WSRT Radio Observations
  30. radio observations, GRB 040924
  31. IBAS Alert 1991. Not a real GRB
  32. GRB040929,optical observation
  33. GRB040924,optical observation
  34. GRB040924, RTT150 optical observation
  35. GRB 040924: detection of possible host galaxy by Subaru
  36. GRB040924, RTT150 optical observation
  37. GRB040924: KAIT observations
  38. GRB040924: Afterglow magnitude at t=17.5hr
  39. GRB 040924: WSRT Radio Observations
  40. GRB 040924: NIR finding chart
  41. GRB040924 : Optical candidate observations at Lulin observatory
  42. GRB040924 : Optical candidate observations at Lulin observatory
  43. GRB 040924: Subaru NIR observation
  44. GRB 040924: RTT150 optical observations
  45. GRB 040924, optical follow-up
  46. IPN triangulation of GRB040924 (H3564)
  47. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  48. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  49. XRF040916: continuing decay of OT
  50. TAROT Observations of GRB 040916 (HETE #3558)
  51. XRF040916, optical observations
  52. XRF040916: Optical Transient Candidate by Subaru
  53. GRB040916 optical limits 17 min after GRB
  54. XRF 040912 (=H3557): Spectral and Temporal Properties
  55. XRF040916, Ic observations
  56. XRF040912, BVRcIc field calibration
  57. XRF040916, BVRcIc field calibration
  58. GRB040916: Archival optical observations
  59. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  60. GRB040916: Optical observations
  61. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  62. GRB040912 (= H3557): Chandra Observations Scheduled
  63. GRB 040912: Optical Observations
  64. GRB/XRF040912,optical observations
  65. GRB 040912, BVRI observations
  66. Optical observations of GRB/XRF 040912 = HETE 3557
  67. An intense burst from SGR1806-20
  68. IBAS GRB Alerts 1978-1980
  69. Optical observations of field of GRB040912
  70. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  71. GRB 040827: XMM-Newton data
  72. GRB040903 - A XRF?
  73. GRB040827: analysis of the XMM-Newton observation
  74. GRB 040903 - INTEGRAL data analysis
  75. IBAS Alert 1974. Not a real GRB
  76. Very bright burst detected from SGR 1806-20
  77. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  78. Possible GRB 040903 - further analysis
  79. Possible GRB 040903 detected with INTEGRAL
  80. GRB 040827 - Radio Observations
  81. XMM-Newton Images of GRB 040827
  82. GRB 040827: optical and NIR observations at the VLT
  83. GRB 040827: UKIRT - 2nd epoch K-band imaging
  84. GRB 040827: 2nd epoch of Magellan K-band imaging
  85. GRB 040827: K imaging - no evidence of variability
  86. GRB 040827: Detection of NIR afterglow
  87. GRB 040827: Possible detection of optical afterglow
  88. GRB 040827: RTT150 optical observations
  89. GRB040825A: optical limit before GRB
  90. GRB 040825B: Optical observations
  91. GRB040827 optical observations
  92. GRB 040827 : Planned XMM-Newton observation
  93. GRB 040827 - Refined position
  94. GRB 040827 : peak flux
  95. GRB 040827 - A long GRB detected by INTEGRAL
  96. GRB040825B, BVRcIc field photometry
  97. GRB040825A, BVRcIc field photometry
  98. GCN GRB OBSERBATION REPORT
  99. GRB 040825A,optical observations
  100. Increase of SGR 1806-20 activity

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