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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"

35941 results found.

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

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