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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"

32503 results found.

  1. GRB041211, Faulkes Telescope optical observation
  2. GRB041211, BVRcIc field calibration
  3. GRB 041211: Infrared Observations
  4. GRB 041211: Optical follow-up in East Asian region
  5. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  6. GRB041015: Near-Infrared observations
  7. GRB 040924: Afterglow Color
  8. GRB 041006: GETS Optical Afterglow Observation
  9. Summary of the recent bursts from SGR 1806-20
  10. GRB 041006: Optical Observations
  11. GRB041006, late-time optical photometry
  12. GRB041006: RTT150 Optical Observations
  13. GRB041015 : Multi epoch optical observations
  14. GRB041006: RTT150 Optical Observations
  15. GRB 041016: Optical limits
  16. GRB 041015: Optical Observations at Rikubetsu
  17. GRB041006: Near Infrared observations
  18. GRB040924, BVRcIc field calibration
  19. GRB 041015: Optical limit at Osaka University
  20. GRB041015 : Optical follow-up at Kiso
  21. GRB 041006 R observations in Loiano
  22. GRB041006: VLT observations of the afterglow and host galaxy
  23. GRB041006: Optical observations and Potential host galaxy
  24. GRB041006, BVRcIc field calibration
  25. GRB 040924: VLT spectroscopy
  26. GRB 041006: SARA afterglow observations
  27. GRB041006, optical observation in CrAO
  28. Search for SN light in XRF 040912 with MEGACAM
  29. GRB 040916: Afterglow Color at Early Times
  30. GRB 041006 Optical afterglow observations
  31. GRB 041006: BR observations with VATT
  32. GRB 041006: Redshift confirmed
  33. GRB041006: Liverpool Telescope optical observations
  34. GRB 041006: Colour measurement
  35. GRB041006: break in the light curve
  36. GRB 041006: Radio Observations
  37. GRB 041006 : optical follow-up observation at Lulin Observatory
  38. GRB 041006 : Optical follow-up observation at TAROT
  39. GRB041006: Optical photometry and spectroscopy at TNG
  40. GRB 041006: presice astrometry
  41. GRB041006 (= H3570): Chandra Observations In Progress
  42. GRB 041006 : optical observation at Bisei
  43. GRB041006, optical I observation
  44. GRB041006 (=HETE3570): optical observations
  45. ROTSE-IIIa Observations of GRB 041006
  46. GRB041006, optical observation
  47. GRB041006, submillimetre observations
  48. GRB041006: MASTER optical observations
  49. GRB 041006: Optical decay
  50. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  51. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  52. GRB041006: Fading of optical afterglow candidate
  53. GRB 041006 : Optical follow-up observation at KISO
  54. GRB 041006: Finding chart
  55. GRB 041006: Optical afterglow candidate
  56. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  57. XRF 020903: Observations of the Host Galaxy (authors)
  58. XRF 020903: Observations of the Host Galaxy
  59. GRB 040924: Second Epoch WSRT Radio Observations
  60. radio observations, GRB 040924
  61. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  62. GRB040924,optical observation
  63. GRB040924, RTT150 optical observation
  64. GRB040924,optical observation
  65. GRB 040924: detection of possible host galaxy by Subaru
  66. GRB040924, RTT150 optical observation
  67. GRB040924: KAIT observations
  68. GRB040924: Afterglow magnitude at t=17.5hr
  69. GRB 040924: WSRT Radio Observations
  70. GRB 040924: NIR finding chart
  71. GRB040924 : Optical candidate observations at Lulin observatory
  72. GRB040924 : Optical candidate observations at Lulin observatory
  73. GRB 040924: Subaru NIR observation
  74. GRB 040924: RTT150 optical observations
  75. GRB 040924, optical follow-up
  76. GRB040924: MASTER: OT decay
  77. IPN triangulation of GRB040924 (H3564)
  78. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  79. XRF 040912: Radio Observations
  80. XRF 040916: Radio Observations
  81. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  82. XRF040916: continuing decay of OT
  83. TAROT Observations of GRB 040916 (HETE #3558)
  84. GRB040912(=H3557): Candidate Optical Afterglow
  85. XRF040916, optical observations
  86. XRF040916: Optical Transient Candidate by Subaru
  87. XRF 040912, identification of CXO sources
  88. XRF040916, Ic observations
  89. XRF040916: optical follow-up observations
  90. XRF040912, BVRcIc field calibration
  91. XRF040916, BVRcIc field calibration
  92. GRB040916: Archival optical observations
  93. XRF 040916, optical follow-up
  94. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  95. GRB040916: Optical observations
  96. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  97. GRB040916 (= H3558): A Long XRF Localized by HETE
  98. GRB040912 (= H3557): Chandra Observations Scheduled
  99. GRB 040912, BVRI observations
  100. GRB040912 : Kiso Optical follow-up observation

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