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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"

36144 results found.

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

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