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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"

32501 results found.

  1. GRB 041211: Infrared Observations
  2. GRB 041211: Optical follow-up in East Asian region
  3. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  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. GRB041006: RTT150 Optical Observations
  11. GRB041015 : Multi epoch optical observations
  12. GRB041006: RTT150 Optical Observations
  13. GRB 041016: Optical limits
  14. GRB 041015: Optical Observations at Rikubetsu
  15. GRB041006: Near Infrared observations
  16. GRB040924, BVRcIc field calibration
  17. GRB 041015: Optical limit at Osaka University
  18. GRB041015 : Optical follow-up at Kiso
  19. GRB 041006 R observations in Loiano
  20. GRB041006: VLT observations of the afterglow and host galaxy
  21. GRB041006: Optical observations and Potential host galaxy
  22. GRB041006, BVRcIc field calibration
  23. GRB 040924: VLT spectroscopy
  24. GRB 041006: SARA afterglow observations
  25. GRB041006, optical observation in CrAO
  26. Search for SN light in XRF 040912 with MEGACAM
  27. GRB 040916: Afterglow Color at Early Times
  28. GRB 041006 Optical afterglow observations
  29. GRB 041006: BR observations with VATT
  30. GRB 041006: Redshift confirmed
  31. GRB041006: Liverpool Telescope optical observations
  32. GRB 041006: Colour measurement
  33. GRB041006: break in the light curve
  34. GRB 041006: Radio Observations
  35. GRB 041006 : optical follow-up observation at Lulin Observatory
  36. GRB 041006 : Optical follow-up observation at TAROT
  37. GRB041006: Optical photometry and spectroscopy at TNG
  38. GRB 041006: presice astrometry
  39. GRB041006 (= H3570): Chandra Observations In Progress
  40. GRB 041006 : optical observation at Bisei
  41. GRB041006, optical I observation
  42. GRB041006 (=HETE3570): optical observations
  43. ROTSE-IIIa Observations of GRB 041006
  44. GRB041006, optical observation
  45. GRB041006, submillimetre observations
  46. GRB041006: MASTER optical observations
  47. GRB 041006: Optical decay
  48. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  49. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  50. GRB041006: Fading of optical afterglow candidate
  51. GRB 041006 : Optical follow-up observation at KISO
  52. GRB 041006: Finding chart
  53. GRB 041006: Optical afterglow candidate
  54. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  55. XRF 020903: Observations of the Host Galaxy (authors)
  56. XRF 020903: Observations of the Host Galaxy
  57. GRB 040924: Second Epoch WSRT Radio Observations
  58. radio observations, GRB 040924
  59. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  60. GRB040924,optical observation
  61. GRB040924, RTT150 optical observation
  62. GRB040924,optical observation
  63. GRB 040924: detection of possible host galaxy by Subaru
  64. GRB040924, RTT150 optical observation
  65. GRB040924: KAIT observations
  66. GRB040924: Afterglow magnitude at t=17.5hr
  67. GRB 040924: WSRT Radio Observations
  68. GRB 040924: NIR finding chart
  69. GRB040924 : Optical candidate observations at Lulin observatory
  70. GRB040924 : Optical candidate observations at Lulin observatory
  71. GRB 040924: Subaru NIR observation
  72. GRB 040924: RTT150 optical observations
  73. GRB 040924, optical follow-up
  74. GRB040924: MASTER: OT decay
  75. IPN triangulation of GRB040924 (H3564)
  76. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  77. XRF 040912: Radio Observations
  78. XRF 040916: Radio Observations
  79. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  80. XRF040916: continuing decay of OT
  81. TAROT Observations of GRB 040916 (HETE #3558)
  82. GRB040912(=H3557): Candidate Optical Afterglow
  83. XRF040916, optical observations
  84. XRF040916: Optical Transient Candidate by Subaru
  85. XRF 040912, identification of CXO sources
  86. XRF040916, Ic observations
  87. XRF040916: optical follow-up observations
  88. XRF040912, BVRcIc field calibration
  89. XRF040916, BVRcIc field calibration
  90. GRB040916: Archival optical observations
  91. XRF 040916, optical follow-up
  92. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  93. GRB040916: Optical observations
  94. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  95. GRB040916 (= H3558): A Long XRF Localized by HETE
  96. GRB040912 (= H3557): Chandra Observations Scheduled
  97. GRB 040912, BVRI observations
  98. GRB040912 : Kiso Optical follow-up observation
  99. IBAS GRB Alerts 1978-1980
  100. Optical observations of field of GRB040912

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