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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"

34060 results found.

  1. GRB 041015: Optical limit at Osaka University
  2. GRB041015 : Optical follow-up at Kiso
  3. GRB 041015 - A long GRB detected by INTEGRAL
  4. GRB 041006 R observations in Loiano
  5. GRB041006: VLT observations of the afterglow and host galaxy
  6. GRB041006: Optical observations and Potential host galaxy
  7. GRB041006, BVRcIc field calibration
  8. GRB 040924: VLT spectroscopy
  9. GRB 041006: SARA afterglow observations
  10. Search for SN light in XRF 040912 with MEGACAM
  11. GRB 040916: Afterglow Color at Early Times
  12. GRB 041006 Optical afterglow observations
  13. IBAS GRB Alert # 2010
  14. GRB 041006: BR observations with VATT
  15. GRB 041006: Redshift confirmed
  16. GRB041006: Liverpool Telescope optical observations
  17. GRB 041006: Colour measurement
  18. GRB041006: break in the light curve
  19. GRB 041006: Radio Observations
  20. GRB041006, further submilllimetre observations
  21. GRB 041006 : optical follow-up observation at Lulin Observatory
  22. GRB 041006 : Optical follow-up observation at TAROT
  23. GRB041006: Optical photometry and spectroscopy at TNG
  24. GRB 041006: presice astrometry
  25. GRB041006 (= H3570): Chandra Observations In Progress
  26. GRB 041006 : optical observation at Bisei
  27. GRB041006 (=HETE3570): optical observations
  28. ROTSE-IIIa Observations of GRB 041006
  29. GRB041006, submillimetre observations
  30. GRB041006: MASTER optical observations
  31. GRB 041006: Optical decay
  32. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  33. GRB 041006 : Optical follow-up observation at KISO
  34. GRB 041006: Finding chart
  35. GRB 041006: Optical afterglow candidate
  36. XRF 020903: Observations of the Host Galaxy (authors)
  37. GRB 040924: Second Epoch WSRT Radio Observations
  38. radio observations, GRB 040924
  39. IBAS Alert 1991. Not a real GRB
  40. GRB040929,optical observation
  41. GRB040924,optical observation
  42. GRB040924, RTT150 optical observation
  43. GRB 040924: detection of possible host galaxy by Subaru
  44. GRB040924, RTT150 optical observation
  45. GRB040924: KAIT observations
  46. GRB040924: Afterglow magnitude at t=17.5hr
  47. GRB 040924: WSRT Radio Observations
  48. GRB 040924: NIR finding chart
  49. GRB040924 : Optical candidate observations at Lulin observatory
  50. GRB040924 : Optical candidate observations at Lulin observatory
  51. GRB 040924: Subaru NIR observation
  52. GRB 040924: RTT150 optical observations
  53. GRB 040924, optical follow-up
  54. IPN triangulation of GRB040924 (H3564)
  55. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  56. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  57. XRF040916: continuing decay of OT
  58. TAROT Observations of GRB 040916 (HETE #3558)
  59. XRF040916, optical observations
  60. XRF040916: Optical Transient Candidate by Subaru
  61. GRB040916 optical limits 17 min after GRB
  62. XRF 040912 (=H3557): Spectral and Temporal Properties
  63. XRF040916, Ic observations
  64. XRF040912, BVRcIc field calibration
  65. XRF040916, BVRcIc field calibration
  66. GRB040916: Archival optical observations
  67. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  68. GRB040916: Optical observations
  69. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  70. GRB040912 (= H3557): Chandra Observations Scheduled
  71. GRB 040912: Optical Observations
  72. GRB/XRF040912,optical observations
  73. GRB 040912, BVRI observations
  74. Optical observations of GRB/XRF 040912 = HETE 3557
  75. An intense burst from SGR1806-20
  76. IBAS GRB Alerts 1978-1980
  77. Optical observations of field of GRB040912
  78. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  79. GRB 040827: XMM-Newton data
  80. GRB040903 - A XRF?
  81. GRB040827: analysis of the XMM-Newton observation
  82. GRB 040903 - INTEGRAL data analysis
  83. IBAS Alert 1974. Not a real GRB
  84. Very bright burst detected from SGR 1806-20
  85. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  86. Possible GRB 040903 - further analysis
  87. Possible GRB 040903 detected with INTEGRAL
  88. GRB 040827 - Radio Observations
  89. XMM-Newton Images of GRB 040827
  90. GRB 040827: optical and NIR observations at the VLT
  91. GRB 040827: UKIRT - 2nd epoch K-band imaging
  92. GRB 040827: 2nd epoch of Magellan K-band imaging
  93. GRB 040827: K imaging - no evidence of variability
  94. GRB 040827: Detection of NIR afterglow
  95. GRB 040827: Possible detection of optical afterglow
  96. GRB 040827: RTT150 optical observations
  97. GRB040825A: optical limit before GRB
  98. GRB 040825B: Optical observations
  99. GRB040827 optical observations
  100. GRB 040827 : Planned XMM-Newton observation

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