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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"

35952 results found.

  1. GRB041006: Near Infrared observations
  2. GRB 041016: Optical limit
  3. GRB 041015 R band observations
  4. GRB040924, BVRcIc field calibration
  5. GRB041015: MASTER: Optical observations
  6. GRB041015,optical observation
  7. GRB 041015: Optical limit at Osaka University
  8. GRB041015 : Optical follow-up at Kiso
  9. GRB 041015 - A long GRB detected by INTEGRAL
  10. GRB 041006 R observations in Loiano
  11. GRB041006: VLT observations of the afterglow and host galaxy
  12. GRB041006: Optical observations and Potential host galaxy
  13. GRB041006, BVRcIc field calibration
  14. GRB 040924: VLT spectroscopy
  15. GRB 041006: SARA afterglow observations
  16. Search for SN light in XRF 040912 with MEGACAM
  17. GRB 040916: Afterglow Color at Early Times
  18. GRB 041006 Optical afterglow observations
  19. IBAS GRB Alert # 2010
  20. GRB 041006: BR observations with VATT
  21. GRB 041006: Redshift confirmed
  22. GRB041006: Liverpool Telescope optical observations
  23. GRB 041006: Colour measurement
  24. GRB041006: break in the light curve
  25. GRB 041006: Radio Observations
  26. GRB041006, further submilllimetre observations
  27. GRB 041006 : optical follow-up observation at Lulin Observatory
  28. GRB 041006 : Optical follow-up observation at TAROT
  29. GRB041006: Optical photometry and spectroscopy at TNG
  30. GRB 041006: presice astrometry
  31. GRB041006 (= H3570): Chandra Observations In Progress
  32. GRB 041006 : optical observation at Bisei
  33. GRB041006 (=HETE3570): optical observations
  34. ROTSE-IIIa Observations of GRB 041006
  35. GRB041006, submillimetre observations
  36. GRB041006: MASTER optical observations
  37. GRB 041006: Optical decay
  38. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  39. GRB 041006 : Optical follow-up observation at KISO
  40. GRB 041006: Finding chart
  41. GRB 041006: Optical afterglow candidate
  42. XRF 020903: Observations of the Host Galaxy (authors)
  43. GRB 040924: Second Epoch WSRT Radio Observations
  44. radio observations, GRB 040924
  45. IBAS Alert 1991. Not a real GRB
  46. GRB040929,optical observation
  47. GRB040924,optical observation
  48. GRB040924, RTT150 optical observation
  49. GRB 040924: detection of possible host galaxy by Subaru
  50. GRB040924, RTT150 optical observation
  51. GRB040924: KAIT observations
  52. GRB040924: Afterglow magnitude at t=17.5hr
  53. GRB 040924: WSRT Radio Observations
  54. GRB 040924: NIR finding chart
  55. GRB040924 : Optical candidate observations at Lulin observatory
  56. GRB040924 : Optical candidate observations at Lulin observatory
  57. GRB 040924: Subaru NIR observation
  58. GRB 040924: RTT150 optical observations
  59. GRB 040924, optical follow-up
  60. IPN triangulation of GRB040924 (H3564)
  61. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  62. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  63. XRF040916: continuing decay of OT
  64. TAROT Observations of GRB 040916 (HETE #3558)
  65. XRF040916, optical observations
  66. XRF040916: Optical Transient Candidate by Subaru
  67. GRB040916 optical limits 17 min after GRB
  68. XRF 040912 (=H3557): Spectral and Temporal Properties
  69. XRF040916, Ic observations
  70. XRF040912, BVRcIc field calibration
  71. XRF040916, BVRcIc field calibration
  72. GRB040916: Archival optical observations
  73. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  74. GRB040916: Optical observations
  75. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  76. GRB040912 (= H3557): Chandra Observations Scheduled
  77. GRB 040912: Optical Observations
  78. GRB/XRF040912,optical observations
  79. GRB 040912, BVRI observations
  80. Optical observations of GRB/XRF 040912 = HETE 3557
  81. An intense burst from SGR1806-20
  82. IBAS GRB Alerts 1978-1980
  83. Optical observations of field of GRB040912
  84. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  85. GRB 040827: XMM-Newton data
  86. GRB040903 - A XRF?
  87. GRB040827: analysis of the XMM-Newton observation
  88. GRB 040903 - INTEGRAL data analysis
  89. IBAS Alert 1974. Not a real GRB
  90. Very bright burst detected from SGR 1806-20
  91. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  92. Possible GRB 040903 - further analysis
  93. Possible GRB 040903 detected with INTEGRAL
  94. GRB 040827 - Radio Observations
  95. XMM-Newton Images of GRB 040827
  96. GRB 040827: optical and NIR observations at the VLT
  97. GRB 040827: UKIRT - 2nd epoch K-band imaging
  98. GRB 040827: 2nd epoch of Magellan K-band imaging
  99. GRB 040827: K imaging - no evidence of variability
  100. GRB 040827: Detection of NIR afterglow

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