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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"

3028 results found.

  1. GRB 060206: Swift/UVOT Observations
  2. GRB 060209(?): Swift-BAT detection of a possible burst
  3. GRB060206: Swift-BAT detection of a burst
  4. GRB060124: detailed XRT analysis
  5. GRB 060123: Swift detection of a very long, faint burst
  6. GRB 060117: PROMPT Observations
  7. GRB 060116: PROMPT Observations
  8. GRB 060105: Radio observations
  9. GRB 060102 - no XRT afterglow
  10. GRB 051210: Swift/UVOT upper limits
  11. GRB051210: Swift UVOT Observation
  12. GRB 051210: Swift detection of a burst
  13. GRB051111: Swift/UVOT Observations
  14. GRB 051111: Swift-BAT refined analysis
  15. GRB051103: MASTER: OT limit and host galaxy candidates
  16. GRB051028: Swift-XRT refined analysis
  17. GRB051105A: Swift/UVOT Observations
  18. GRB051103:_MASTER_optical_observations
  19. GRB051028: WHT optical candidate
  20. GRB051028: Swift XRT Position
  21. SGR 1806-20: continued moderate activity seen with INTEGRAL
  22. GRB051012: Swift-XRT analysis
  23. GRB 051021B: Refined analysis of the Swift-BAT burst
  24. GRB 051021: SOAR NIR Observations
  25. Swift-BAT triggered on a posible CR Shower or possible GRB
  26. GRB 051012: Swift-BAT detection of burst yesterday
  27. GRB 050922B: optical limit
  28. GRB 050906: Possible X-ray Counterpart
  29. GRB 050906: MARGE Optical Limits
  30. GRB 050824: MDM Observations
  31. GRB050824: First 2 hours of power low optical decay?
  32. GRB050824: MASTER final analysis of the OT observations
  33. GRB050822: Swift/UVOT upper limits
  34. GRB050813: Maidanak I-band observations
  35. GRB 050822: Swift detection of a long burst
  36. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  37. GRB050803: CrAO optical observations, no OT candidate
  38. GRB 050805b: OHP optical limits
  39. GRB 050803: Magellan Observations
  40. GRB 050803: early Swift XRT analysis results
  41. GRB 050730: OHP optical observations
  42. GRB 050802: early Swift XRT analysis results
  43. GRB 050802: Swift/UVOT observations
  44. GRB 050802: XRT position
  45. Swift-BAT trigger 147918 is not a real GRB
  46. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  47. GRB050716, optical observation
  48. GRB 050713, R-band observations at NOT
  49. GRB050607: prompt REM observations
  50. GRB050525: Super-LOTIS observations
  51. GRB 050525: Optical observation
  52. XRF050522: NIR observations of XRT candidate
  53. XRF 050522: Swift XRT refined analysis
  54. GRB050502b: Early Observation
  55. GRB 050505, early TAROT observation
  56. GRB050509a: Swift UVOT observations
  57. GRB 050509a: Swift XRT Position
  58. Swift Detection of the Burst GRB050509
  59. GRB 050505: Keck I-band Magnitude
  60. GRB 050505: early time observations
  61. GRB (?) 050504: IR Observations, Intriguing Source
  62. GRB050326: optical limit
  63. Swift Detection of GRB 050319
  64. RXTE Observations of GRB050318
  65. GRB050309: CONCAM pre-trigger and trigger coincident optical
  66. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  67. GRB 050219b: Swift XRT Position
  68. GRB050215b: Swift UVOT Detection of Afterglow Emission
  69. GRB 050215b: XRT confirmation of IR afterglow candidate
  70. GRB 050215B: candidate afterglow
  71. GRB 050215B: UKIRT K-band imaging
  72. GRB 050215b: Swift XRT Observations
  73. GRB050126: MASTER optical limit for KECK OT
  74. GRB050126: MASTER optical observations
  75. GRB050117: Palomar WIRC Ks-band observations
  76. GRB 041217: Optical observations
  77. GRB041226: ROTSE-III Optical Observations
  78. GRB041218: Continued P60 Optical Observations
  79. GRB 041218: Optical observations
  80. GRB041211,optical observation
  81. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  82. SGR 1806-20 still active
  83. GRB040924,optical observation
  84. IBAS GRB Alerts 1978-1980
  85. GRB040903 - A XRF?
  86. XRF040812: GMRT observations
  87. GRB 040812: Optical counterparts of CXO sources
  88. GRB 040812: Keck and LCO optical observations
  89. GRB 040812: Keck and LCO observations
  90. GRB040624: optical monitoring at TNG
  91. XRF040701: Second-Epoch Chandra Observations
  92. XRF040701: VLA Observations
  93. XRF040701: First-Epoch Chandra Observations
  94. IPN Summary of SGR1806-20 Activity in 2004
  95. MASTER: HETE Alert 3274 optical observation
  96. GRB040511: Candidate optical/NIR afterglow
  97. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  98. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  99. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  100. GRB040106: refined X-ray transient position

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