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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"

35958 results found.

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

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