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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"

36160 results found.

  1. GRB 041016:Optical limit during first minute
  2. GRB041016: MASTER: Optical observations
  3. GRB 041015: Optical Observations at Rikubetsu
  4. GRB041006: Near Infrared observations
  5. GRB 041016: Optical limit
  6. GRB 041015 R band observations
  7. GRB040924, BVRcIc field calibration
  8. GRB041015: MASTER: Optical observations
  9. GRB041015,optical observation
  10. GRB 041015: Optical limit at Osaka University
  11. GRB041015 : Optical follow-up at Kiso
  12. GRB 041015 - A long GRB detected by INTEGRAL
  13. GRB 041006 R observations in Loiano
  14. GRB041006: VLT observations of the afterglow and host galaxy
  15. GRB041006: Optical observations and Potential host galaxy
  16. GRB041006, BVRcIc field calibration
  17. GRB 040924: VLT spectroscopy
  18. GRB 041006: SARA afterglow observations
  19. Search for SN light in XRF 040912 with MEGACAM
  20. GRB 040916: Afterglow Color at Early Times
  21. GRB 041006 Optical afterglow observations
  22. IBAS GRB Alert # 2010
  23. GRB 041006: BR observations with VATT
  24. GRB 041006: Redshift confirmed
  25. GRB041006: Liverpool Telescope optical observations
  26. GRB 041006: Colour measurement
  27. GRB041006: break in the light curve
  28. GRB 041006: Radio Observations
  29. GRB041006, further submilllimetre observations
  30. GRB 041006 : optical follow-up observation at Lulin Observatory
  31. GRB 041006 : Optical follow-up observation at TAROT
  32. GRB041006: Optical photometry and spectroscopy at TNG
  33. GRB 041006: presice astrometry
  34. GRB041006 (= H3570): Chandra Observations In Progress
  35. GRB 041006 : optical observation at Bisei
  36. GRB041006 (=HETE3570): optical observations
  37. ROTSE-IIIa Observations of GRB 041006
  38. GRB041006, submillimetre observations
  39. GRB041006: MASTER optical observations
  40. GRB 041006: Optical decay
  41. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  42. GRB 041006 : Optical follow-up observation at KISO
  43. GRB 041006: Finding chart
  44. GRB 041006: Optical afterglow candidate
  45. XRF 020903: Observations of the Host Galaxy (authors)
  46. GRB 040924: Second Epoch WSRT Radio Observations
  47. radio observations, GRB 040924
  48. IBAS Alert 1991. Not a real GRB
  49. GRB040929,optical observation
  50. GRB040924,optical observation
  51. GRB040924, RTT150 optical observation
  52. GRB 040924: detection of possible host galaxy by Subaru
  53. GRB040924, RTT150 optical observation
  54. GRB040924: KAIT observations
  55. GRB040924: Afterglow magnitude at t=17.5hr
  56. GRB 040924: WSRT Radio Observations
  57. GRB 040924: NIR finding chart
  58. GRB040924 : Optical candidate observations at Lulin observatory
  59. GRB040924 : Optical candidate observations at Lulin observatory
  60. GRB 040924: Subaru NIR observation
  61. GRB 040924: RTT150 optical observations
  62. GRB 040924, optical follow-up
  63. IPN triangulation of GRB040924 (H3564)
  64. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  65. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  66. XRF040916: continuing decay of OT
  67. TAROT Observations of GRB 040916 (HETE #3558)
  68. XRF040916, optical observations
  69. XRF040916: Optical Transient Candidate by Subaru
  70. GRB040916 optical limits 17 min after GRB
  71. XRF 040912 (=H3557): Spectral and Temporal Properties
  72. XRF040916, Ic observations
  73. XRF040912, BVRcIc field calibration
  74. XRF040916, BVRcIc field calibration
  75. GRB040916: Archival optical observations
  76. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  77. GRB040916: Optical observations
  78. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  79. GRB040912 (= H3557): Chandra Observations Scheduled
  80. GRB 040912: Optical Observations
  81. GRB/XRF040912,optical observations
  82. GRB 040912, BVRI observations
  83. Optical observations of GRB/XRF 040912 = HETE 3557
  84. An intense burst from SGR1806-20
  85. IBAS GRB Alerts 1978-1980
  86. Optical observations of field of GRB040912
  87. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  88. GRB 040827: XMM-Newton data
  89. GRB040903 - A XRF?
  90. GRB040827: analysis of the XMM-Newton observation
  91. GRB 040903 - INTEGRAL data analysis
  92. IBAS Alert 1974. Not a real GRB
  93. Very bright burst detected from SGR 1806-20
  94. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  95. Possible GRB 040903 - further analysis
  96. Possible GRB 040903 detected with INTEGRAL
  97. GRB 040827 - Radio Observations
  98. XMM-Newton Images of GRB 040827
  99. GRB 040827: optical and NIR observations at the VLT
  100. GRB 040827: UKIRT - 2nd epoch K-band imaging

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