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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"

32508 results found.

  1. GRB041217: The First GRB Located On-Board Swift
  2. GRB041211: Faulkes Telescope continued optical monitoring
  3. Optical Transient in Lynx not a GRB
  4. Optical transient (GRB?) in Lynx
  5. GRB041211: Continued P60 Observations
  6. GRB041211, Faulkes Telescope optical observation
  7. GRB041211, BVRcIc field calibration
  8. GRB 041211: Infrared Observations
  9. GRB 041211: Optical follow-up in East Asian region
  10. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  11. GRB041015: Near-Infrared observations
  12. GRB 040924: Afterglow Color
  13. GRB 041006: GETS Optical Afterglow Observation
  14. Summary of the recent bursts from SGR 1806-20
  15. GRB 041006: Optical Observations
  16. GRB041006, late-time optical photometry
  17. GRB041006: RTT150 Optical Observations
  18. GRB041015 : Multi epoch optical observations
  19. GRB041006: RTT150 Optical Observations
  20. GRB 041016: Optical limits
  21. GRB 041015: Optical Observations at Rikubetsu
  22. GRB041006: Near Infrared observations
  23. GRB040924, BVRcIc field calibration
  24. GRB 041015: Optical limit at Osaka University
  25. GRB041015 : Optical follow-up at Kiso
  26. GRB 041006 R observations in Loiano
  27. GRB041006: VLT observations of the afterglow and host galaxy
  28. GRB041006: Optical observations and Potential host galaxy
  29. GRB041006, BVRcIc field calibration
  30. GRB 040924: VLT spectroscopy
  31. GRB 041006: SARA afterglow observations
  32. GRB041006, optical observation in CrAO
  33. Search for SN light in XRF 040912 with MEGACAM
  34. GRB 040916: Afterglow Color at Early Times
  35. GRB 041006 Optical afterglow observations
  36. GRB 041006: BR observations with VATT
  37. GRB 041006: Redshift confirmed
  38. GRB041006: Liverpool Telescope optical observations
  39. GRB 041006: Colour measurement
  40. GRB041006: break in the light curve
  41. GRB 041006: Radio Observations
  42. GRB 041006 : optical follow-up observation at Lulin Observatory
  43. GRB 041006 : Optical follow-up observation at TAROT
  44. GRB041006: Optical photometry and spectroscopy at TNG
  45. GRB 041006: presice astrometry
  46. GRB041006 (= H3570): Chandra Observations In Progress
  47. GRB 041006 : optical observation at Bisei
  48. GRB041006, optical I observation
  49. GRB041006 (=HETE3570): optical observations
  50. ROTSE-IIIa Observations of GRB 041006
  51. GRB041006, optical observation
  52. GRB041006, submillimetre observations
  53. GRB041006: MASTER optical observations
  54. GRB 041006: Optical decay
  55. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  56. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  57. GRB041006: Fading of optical afterglow candidate
  58. GRB 041006 : Optical follow-up observation at KISO
  59. GRB 041006: Finding chart
  60. GRB 041006: Optical afterglow candidate
  61. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  62. XRF 020903: Observations of the Host Galaxy (authors)
  63. XRF 020903: Observations of the Host Galaxy
  64. GRB 040924: Second Epoch WSRT Radio Observations
  65. radio observations, GRB 040924
  66. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  67. GRB040924,optical observation
  68. GRB040924, RTT150 optical observation
  69. GRB040924,optical observation
  70. GRB 040924: detection of possible host galaxy by Subaru
  71. GRB040924, RTT150 optical observation
  72. GRB040924: KAIT observations
  73. GRB040924: Afterglow magnitude at t=17.5hr
  74. GRB 040924: WSRT Radio Observations
  75. GRB 040924: NIR finding chart
  76. GRB040924 : Optical candidate observations at Lulin observatory
  77. GRB040924 : Optical candidate observations at Lulin observatory
  78. GRB 040924: Subaru NIR observation
  79. GRB 040924: RTT150 optical observations
  80. GRB 040924, optical follow-up
  81. GRB040924: MASTER: OT decay
  82. IPN triangulation of GRB040924 (H3564)
  83. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  84. XRF 040912: Radio Observations
  85. XRF 040916: Radio Observations
  86. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  87. XRF040916: continuing decay of OT
  88. TAROT Observations of GRB 040916 (HETE #3558)
  89. GRB040912(=H3557): Candidate Optical Afterglow
  90. XRF040916, optical observations
  91. XRF040916: Optical Transient Candidate by Subaru
  92. XRF 040912, identification of CXO sources
  93. XRF040916, Ic observations
  94. XRF040916: optical follow-up observations
  95. XRF040912, BVRcIc field calibration
  96. XRF040916, BVRcIc field calibration
  97. GRB040916: Archival optical observations
  98. XRF 040916, optical follow-up
  99. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  100. GRB040916: Optical observations

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