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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"

35957 results found.

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

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