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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"

35937 results found.

  1. Search for SN light in XRF 040912 with MEGACAM
  2. GRB 040916: Afterglow Color at Early Times
  3. GRB 041006 Optical afterglow observations
  4. IBAS GRB Alert # 2010
  5. GRB 041006: BR observations with VATT
  6. GRB 041006: Redshift confirmed
  7. GRB041006: Liverpool Telescope optical observations
  8. GRB 041006: Colour measurement
  9. GRB041006: break in the light curve
  10. GRB 041006: Radio Observations
  11. GRB041006, further submilllimetre observations
  12. GRB 041006 : optical follow-up observation at Lulin Observatory
  13. GRB 041006 : Optical follow-up observation at TAROT
  14. GRB041006: Optical photometry and spectroscopy at TNG
  15. GRB 041006: presice astrometry
  16. GRB041006 (= H3570): Chandra Observations In Progress
  17. GRB 041006 : optical observation at Bisei
  18. GRB041006 (=HETE3570): optical observations
  19. ROTSE-IIIa Observations of GRB 041006
  20. GRB041006, submillimetre observations
  21. GRB041006: MASTER optical observations
  22. GRB 041006: Optical decay
  23. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  24. GRB 041006 : Optical follow-up observation at KISO
  25. GRB 041006: Finding chart
  26. GRB 041006: Optical afterglow candidate
  27. XRF 020903: Observations of the Host Galaxy (authors)
  28. GRB 040924: Second Epoch WSRT Radio Observations
  29. radio observations, GRB 040924
  30. IBAS Alert 1991. Not a real GRB
  31. GRB040929,optical observation
  32. GRB040924,optical observation
  33. GRB040924, RTT150 optical observation
  34. GRB 040924: detection of possible host galaxy by Subaru
  35. GRB040924, RTT150 optical observation
  36. GRB040924: KAIT observations
  37. GRB040924: Afterglow magnitude at t=17.5hr
  38. GRB 040924: WSRT Radio Observations
  39. GRB 040924: NIR finding chart
  40. GRB040924 : Optical candidate observations at Lulin observatory
  41. GRB040924 : Optical candidate observations at Lulin observatory
  42. GRB 040924: Subaru NIR observation
  43. GRB 040924: RTT150 optical observations
  44. GRB 040924, optical follow-up
  45. IPN triangulation of GRB040924 (H3564)
  46. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  47. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  48. XRF040916: continuing decay of OT
  49. TAROT Observations of GRB 040916 (HETE #3558)
  50. XRF040916, optical observations
  51. XRF040916: Optical Transient Candidate by Subaru
  52. GRB040916 optical limits 17 min after GRB
  53. XRF 040912 (=H3557): Spectral and Temporal Properties
  54. XRF040916, Ic observations
  55. XRF040912, BVRcIc field calibration
  56. XRF040916, BVRcIc field calibration
  57. GRB040916: Archival optical observations
  58. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  59. GRB040916: Optical observations
  60. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  61. GRB040912 (= H3557): Chandra Observations Scheduled
  62. GRB 040912: Optical Observations
  63. GRB/XRF040912,optical observations
  64. GRB 040912, BVRI observations
  65. Optical observations of GRB/XRF 040912 = HETE 3557
  66. An intense burst from SGR1806-20
  67. IBAS GRB Alerts 1978-1980
  68. Optical observations of field of GRB040912
  69. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  70. GRB 040827: XMM-Newton data
  71. GRB040903 - A XRF?
  72. GRB040827: analysis of the XMM-Newton observation
  73. GRB 040903 - INTEGRAL data analysis
  74. IBAS Alert 1974. Not a real GRB
  75. Very bright burst detected from SGR 1806-20
  76. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  77. Possible GRB 040903 - further analysis
  78. Possible GRB 040903 detected with INTEGRAL
  79. GRB 040827 - Radio Observations
  80. XMM-Newton Images of GRB 040827
  81. GRB 040827: optical and NIR observations at the VLT
  82. GRB 040827: UKIRT - 2nd epoch K-band imaging
  83. GRB 040827: 2nd epoch of Magellan K-band imaging
  84. GRB 040827: K imaging - no evidence of variability
  85. GRB 040827: Detection of NIR afterglow
  86. GRB 040827: Possible detection of optical afterglow
  87. GRB 040827: RTT150 optical observations
  88. GRB040825A: optical limit before GRB
  89. GRB 040825B: Optical observations
  90. GRB040827 optical observations
  91. GRB 040827 : Planned XMM-Newton observation
  92. GRB 040827 - Refined position
  93. GRB 040827 : peak flux
  94. GRB 040827 - A long GRB detected by INTEGRAL
  95. GRB040825B, BVRcIc field photometry
  96. GRB040825A, BVRcIc field photometry
  97. GCN GRB OBSERBATION REPORT
  98. GRB 040825A,optical observations
  99. Increase of SGR 1806-20 activity
  100. GRB 040825A: Optical observations.

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