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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. GRB970815: Discovery of Optical Afterglow
  2. Distribution of IBAS Alerts for NON-GRB sources
  3. Triangulation of short GRB 041116 (large error box)
  4. GRB041015: Near-Infrared observations
  5. GRB 040924: Afterglow Color
  6. GRB 041006: GETS Optical Afterglow Observation
  7. Summary of the recent bursts from SGR 1806-20
  8. GRB 041006: Optical Observations
  9. GRB041006, late-time optical photometry
  10. GRB041015, optical observation in CrAO
  11. IBAS GRB Alert # 2034
  12. GRB041006: RTT150 Optical Observations
  13. GRB041015 : Multi epoch optical observations
  14. HST Observations: XRF 040701 and 040812
  15. Bright bursts from SGR1806-20
  16. GRB 041016: BOOTES-2 simultaneous observation
  17. GRB041006: RTT150 Optical Observations
  18. GRB041016,optical observation
  19. GRB 041016: Optical limits
  20. GRB 041016: Optical limits in V, R, I
  21. GRB 041016:Optical limit during first minute
  22. GRB041016: MASTER: Optical observations
  23. GRB 041015: Optical Observations at Rikubetsu
  24. GRB041006: Near Infrared observations
  25. GRB 041016: Optical limit
  26. GRB 041015 R band observations
  27. GRB040924, BVRcIc field calibration
  28. GRB041015: MASTER: Optical observations
  29. GRB041015,optical observation
  30. GRB041006: Fading X-ray Afterglow Observed with Chandra
  31. GRB 041015: Optical limit at Osaka University
  32. GRB041015 : Optical follow-up at Kiso
  33. GRB 041015 - A long GRB detected by INTEGRAL
  34. GRB 041006 R observations in Loiano
  35. GRB041006: VLT observations of the afterglow and host galaxy
  36. GRB041006: Optical observations and Potential host galaxy
  37. GRB041006, BVRcIc field calibration
  38. GRB 040924: VLT spectroscopy
  39. GRB 041006: SARA afterglow observations
  40. GRB041006, optical observation in CrAO
  41. Search for SN light in XRF 040912 with MEGACAM
  42. GRB 040916: Afterglow Color at Early Times
  43. GRB 041006 Optical afterglow observations
  44. IBAS GRB Alert # 2010
  45. GRB 041006: BR observations with VATT
  46. GRB 041006: Redshift confirmed
  47. GRB041006: Liverpool Telescope optical observations
  48. GRB 041006: Colour measurement
  49. GRB041006: break in the light curve
  50. GRB 041006: Radio Observations
  51. GRB041006, further submilllimetre observations
  52. GRB 041006 : optical follow-up observation at Lulin Observatory
  53. GRB 041006 : Optical follow-up observation at TAROT
  54. GRB041006: Optical photometry and spectroscopy at TNG
  55. GRB 041006: presice astrometry
  56. GRB041006 (= H3570): Chandra Observations In Progress
  57. GRB 041006 : optical observation at Bisei
  58. GRB041006, optical I observation
  59. GRB041006 (=HETE3570): optical observations
  60. ROTSE-IIIa Observations of GRB 041006
  61. GRB041006, optical observation
  62. GRB041006, submillimetre observations
  63. GRB041006: MASTER optical observations
  64. GRB041006,optical observation
  65. GRB 041006: Optical decay
  66. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  67. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  68. GRB041006: Fading of optical afterglow candidate
  69. GRB 041006 : Optical follow-up observation at KISO
  70. GRB 041006: Finding chart
  71. GRB 041006: Optical afterglow candidate
  72. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  73. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  74. XRF 020903: Observations of the Host Galaxy (authors)
  75. XRF 020903: Observations of the Host Galaxy
  76. SGR 1806-20 still active
  77. GRB 040924: Second Epoch WSRT Radio Observations
  78. radio observations, GRB 040924
  79. IBAS Alert 1991. Not a real GRB
  80. GRB040929,optical observation
  81. GRB040929: MASTER optical observations
  82. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  83. GRB040924,optical observation
  84. GRB040924, RTT150 optical observation
  85. GRB040924,optical observation
  86. GRB 040924: detection of possible host galaxy by Subaru
  87. GRB040924, RTT150 optical observation
  88. GRB040924: KAIT observations
  89. GRB040924: Afterglow magnitude at t=17.5hr
  90. GRB 040924: WSRT Radio Observations
  91. GRB 040924: NIR finding chart
  92. GRB040924 : Optical candidate observations at Lulin observatory
  93. GRB040924 : Optical candidate observations at Lulin observatory
  94. GRB 040924: Subaru NIR observation
  95. GRB040924: Optical afterglow properties
  96. GRB 040924: RTT150 optical observations
  97. GRB 040924, optical follow-up
  98. GRB040924: MASTER: OT decay
  99. GRB040924: MASTER Optical observations
  100. IPN triangulation of GRB040924 (H3564)

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