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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"

36148 results found.

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

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