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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"

32494 results found.

  1. GRB 041006: Optical Observations
  2. GRB041006, late-time optical photometry
  3. GRB041006: RTT150 Optical Observations
  4. GRB041015 : Multi epoch optical observations
  5. GRB041006: RTT150 Optical Observations
  6. GRB 041016: Optical limits
  7. GRB 041015: Optical Observations at Rikubetsu
  8. GRB041006: Near Infrared observations
  9. GRB040924, BVRcIc field calibration
  10. GRB 041015: Optical limit at Osaka University
  11. GRB041015 : Optical follow-up at Kiso
  12. GRB 041006 R observations in Loiano
  13. GRB041006: VLT observations of the afterglow and host galaxy
  14. GRB041006: Optical observations and Potential host galaxy
  15. GRB041006, BVRcIc field calibration
  16. GRB 040924: VLT spectroscopy
  17. GRB 041006: SARA afterglow observations
  18. GRB041006, optical observation in CrAO
  19. Search for SN light in XRF 040912 with MEGACAM
  20. GRB 040916: Afterglow Color at Early Times
  21. GRB 041006 Optical afterglow observations
  22. GRB 041006: BR observations with VATT
  23. GRB 041006: Redshift confirmed
  24. GRB041006: Liverpool Telescope optical observations
  25. GRB 041006: Colour measurement
  26. GRB041006: break in the light curve
  27. GRB 041006: Radio Observations
  28. GRB 041006 : optical follow-up observation at Lulin Observatory
  29. GRB 041006 : Optical follow-up observation at TAROT
  30. GRB041006: Optical photometry and spectroscopy at TNG
  31. GRB 041006: presice astrometry
  32. GRB041006 (= H3570): Chandra Observations In Progress
  33. GRB 041006 : optical observation at Bisei
  34. GRB041006, optical I observation
  35. GRB041006 (=HETE3570): optical observations
  36. ROTSE-IIIa Observations of GRB 041006
  37. GRB041006, optical observation
  38. GRB041006, submillimetre observations
  39. GRB041006: MASTER optical observations
  40. GRB 041006: Optical decay
  41. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  42. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  43. GRB041006: Fading of optical afterglow candidate
  44. GRB 041006 : Optical follow-up observation at KISO
  45. GRB 041006: Finding chart
  46. GRB 041006: Optical afterglow candidate
  47. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  48. XRF 020903: Observations of the Host Galaxy (authors)
  49. XRF 020903: Observations of the Host Galaxy
  50. GRB 040924: Second Epoch WSRT Radio Observations
  51. radio observations, GRB 040924
  52. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  53. GRB040924,optical observation
  54. GRB040924, RTT150 optical observation
  55. GRB040924,optical observation
  56. GRB 040924: detection of possible host galaxy by Subaru
  57. GRB040924, RTT150 optical observation
  58. GRB040924: KAIT observations
  59. GRB040924: Afterglow magnitude at t=17.5hr
  60. GRB 040924: WSRT Radio Observations
  61. GRB 040924: NIR finding chart
  62. GRB040924 : Optical candidate observations at Lulin observatory
  63. GRB040924 : Optical candidate observations at Lulin observatory
  64. GRB 040924: Subaru NIR observation
  65. GRB 040924: RTT150 optical observations
  66. GRB 040924, optical follow-up
  67. GRB040924: MASTER: OT decay
  68. IPN triangulation of GRB040924 (H3564)
  69. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  70. XRF 040912: Radio Observations
  71. XRF 040916: Radio Observations
  72. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  73. XRF040916: continuing decay of OT
  74. TAROT Observations of GRB 040916 (HETE #3558)
  75. GRB040912(=H3557): Candidate Optical Afterglow
  76. XRF040916, optical observations
  77. XRF040916: Optical Transient Candidate by Subaru
  78. XRF 040912, identification of CXO sources
  79. XRF040916, Ic observations
  80. XRF040916: optical follow-up observations
  81. XRF040912, BVRcIc field calibration
  82. XRF040916, BVRcIc field calibration
  83. GRB040916: Archival optical observations
  84. XRF 040916, optical follow-up
  85. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  86. GRB040916: Optical observations
  87. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  88. GRB040916 (= H3558): A Long XRF Localized by HETE
  89. GRB040912 (= H3557): Chandra Observations Scheduled
  90. GRB 040912, BVRI observations
  91. GRB040912 : Kiso Optical follow-up observation
  92. IBAS GRB Alerts 1978-1980
  93. Optical observations of field of GRB040912
  94. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  95. GRB040903 - A XRF?
  96. GRB040827: analysis of the XMM-Newton observation
  97. GRB040903, REM near-IR observation
  98. GRB 040903 - INTEGRAL data analysis
  99. Very bright burst detected from SGR 1806-20
  100. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)

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