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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"
  1. GRB041211: Ashra Prototype optical observation
  2. GRB041211, Faulkes Telescope optical observation
  3. GRB041211, BVRcIc field calibration
  4. GRB041211,optical observation
  5. GRB 041211: Infrared Observations
  6. GRB 041211: KAIT observations
  7. GRB 041211: Optical follow-up in East Asian region
  8. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  9. GRB041211: P60 optical imaging
  10. GRB970815: Discovery of Optical Afterglow
  11. Distribution of IBAS Alerts for NON-GRB sources
  12. Triangulation of short GRB 041116 (large error box)
  13. GRB041015: Near-Infrared observations
  14. GRB 040924: Afterglow Color
  15. GRB 041006: GETS Optical Afterglow Observation
  16. Summary of the recent bursts from SGR 1806-20
  17. GRB 041006: Optical Observations
  18. GRB041006, late-time optical photometry
  19. GRB041015, optical observation in CrAO
  20. IBAS GRB Alert # 2034
  21. GRB041006: RTT150 Optical Observations
  22. GRB041015 : Multi epoch optical observations
  23. HST Observations: XRF 040701 and 040812
  24. Bright bursts from SGR1806-20
  25. GRB 041016: BOOTES-2 simultaneous observation
  26. GRB041006: RTT150 Optical Observations
  27. GRB041016,optical observation
  28. GRB 041016: Optical limits
  29. GRB 041016: Optical limits in V, R, I
  30. GRB 041016:Optical limit during first minute
  31. GRB041016: MASTER: Optical observations
  32. GRB 041015: Optical Observations at Rikubetsu
  33. GRB041006: Near Infrared observations
  34. GRB 041016: Optical limit
  35. GRB 041015 R band observations
  36. GRB040924, BVRcIc field calibration
  37. GRB041015: MASTER: Optical observations
  38. GRB041015,optical observation
  39. GRB041006: Fading X-ray Afterglow Observed with Chandra
  40. GRB 041015: Optical limit at Osaka University
  41. GRB041015 : Optical follow-up at Kiso
  42. GRB 041015 - A long GRB detected by INTEGRAL
  43. GRB 041006 R observations in Loiano
  44. GRB041006: VLT observations of the afterglow and host galaxy
  45. GRB041006: Optical observations and Potential host galaxy
  46. GRB041006, BVRcIc field calibration
  47. GRB 040924: VLT spectroscopy
  48. GRB 041006: SARA afterglow observations
  49. GRB041006, optical observation in CrAO
  50. Search for SN light in XRF 040912 with MEGACAM
  51. GRB 040916: Afterglow Color at Early Times
  52. GRB 041006 Optical afterglow observations
  53. IBAS GRB Alert # 2010
  54. GRB 041006: BR observations with VATT
  55. GRB 041006: Redshift confirmed
  56. GRB041006: Liverpool Telescope optical observations
  57. GRB 041006: Colour measurement
  58. GRB041006: break in the light curve
  59. GRB 041006: Radio Observations
  60. GRB041006, further submilllimetre observations
  61. GRB 041006 : optical follow-up observation at Lulin Observatory
  62. GRB 041006 : Optical follow-up observation at TAROT
  63. GRB041006: Optical photometry and spectroscopy at TNG
  64. GRB 041006: presice astrometry
  65. GRB041006 (= H3570): Chandra Observations In Progress
  66. GRB 041006 : optical observation at Bisei
  67. GRB041006, optical I observation
  68. GRB041006 (=HETE3570): optical observations
  69. ROTSE-IIIa Observations of GRB 041006
  70. GRB041006, optical observation
  71. GRB041006, submillimetre observations
  72. GRB041006: MASTER optical observations
  73. GRB041006,optical observation
  74. GRB 041006: Optical decay
  75. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  76. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  77. GRB041006: Fading of optical afterglow candidate
  78. GRB 041006 : Optical follow-up observation at KISO
  79. GRB 041006: Finding chart
  80. GRB 041006: Optical afterglow candidate
  81. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  82. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  83. XRF 020903: Observations of the Host Galaxy (authors)
  84. XRF 020903: Observations of the Host Galaxy
  85. SGR 1806-20 still active
  86. GRB 040924: Second Epoch WSRT Radio Observations
  87. radio observations, GRB 040924
  88. IBAS Alert 1991. Not a real GRB
  89. GRB040929,optical observation
  90. GRB040929: MASTER optical observations
  91. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  92. GRB040924,optical observation
  93. GRB040924, RTT150 optical observation
  94. GRB040924,optical observation
  95. GRB 040924: detection of possible host galaxy by Subaru
  96. GRB040924, RTT150 optical observation
  97. GRB040924: KAIT observations
  98. GRB040924: Afterglow magnitude at t=17.5hr
  99. GRB 040924: WSRT Radio Observations
  100. GRB 040924: NIR finding chart

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