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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"

35954 results found.

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

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