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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"

2850 results found.

  1. GRB 050502a: Swift XRT Upper Limit
  2. GRB 050502a: Optical Observations
  3. GRB 050504: Swift XRT position
  4. GRB050502A: Optical Observations
  5. GRB 050502: Confirmed variability of the afterglow candidate +
  6. GRB050502 - Correction on the Optical Candidate from the Liverpool
  7. GRB050502 - Optical Candidate from the Liverpool Telescope
  8. GRB 050502: ROTSE-III Detection of Possible Counterpart
  9. GRB 050422: Swift-BAT refined analysis
  10. Swift Detection of GRB050421
  11. GRB 050416: Radio observations
  12. GRB 050412: Swift XRT Position
  13. GRB 050408: Optical limit at 20 min after the burst
  14. Swift-BAT detection of GRB 050401
  15. GRB 050401: Prompt XRT position
  16. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  17. GRB050315: Radio afterglow
  18. GRB 050315: Optical afterglow identification
  19. GRB 050315: Swift XRT Position
  20. Swift-BAT detection of GRB 050315
  21. GRB050309: CONCAM pre-trigger and trigger coincident optical
  22. Swift trigger 107518: optical observation
  23. GRB 050306: TAROT optical observations
  24. GRB 050215b: XRT confirmation of IR afterglow candidate
  25. GRB 050215b: Swift XRT Source Variability
  26. GRB050128,optical observations
  27. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  28. GRB050126: Updated Swift XRT Position
  29. GRB050126: MASTER optical limit for KECK OT
  30. GRB050126: MASTER optical observations
  31. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  32. GRB 050126: Prompt XRT detection and localization
  33. GRB 050124, SMARTS optical/IR observations
  34. GRB 050124: NIR Candidates from Keck/NIRC
  35. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  36. GRB041219; RXTE ASM Observations
  37. GRB 041219 ,optical observation
  38. Swift-BAT detection of the bright long burst GRB041219
  39. GRB041217: The First GRB Located On-Board Swift
  40. GRB 041211: Infrared Observations
  41. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  42. Triangulation of short GRB 041116 (large error box)
  43. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  44. GRB040924: Optical afterglow properties
  45. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  46. GRB040912 : Kiso Optical follow-up observation
  47. GRB040823,optical observation
  48. GRB 040812: Optical counterparts of CXO sources
  49. CXO observation of GRB 040812
  50. GRB 040812: a long GRB detected by INTEGRAL
  51. IPN Summary of SGR1806-20 Activity in 2004
  52. Activivty of SGR 1806-20
  53. IPN triangulation of GRB040228 (H3066, H3067)
  54. XMM-Newton Images of GRB 040223
  55. IPN triangulation of GRB031027 (small error box)
  56. Lulin optical follow-up observations of GRB031026
  57. IPN triangulation of GRB030926 (short/hard; large error box)
  58. IPN triangulation of GRB030903 (large error box)
  59. IPN triangulation of GRB030801 (large error box)
  60. XRF030723(=H2777): Chandra Observations
  61. XRF030723: Palomar observations and proposed counterpart
  62. XRF 030723, optical observations
  63. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  64. IPN triangulation of GRB030715 (two large error boxes)
  65. GRB 021206, Radio afterglow candidate
  66. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  67. GRB 030329 Optical Observations
  68. GRB030519B (=H2716): A Long, Bright GRB Localized by the HETE WXM
  69. GRB030429 (=H2695): A Long GRB Localized by the HETE WXM and SXC
  70. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  71. IPN triangulation of GRB030422 (two large error boxes)
  72. ROTSE-III prompt optical detections of GRB 030418
  73. GRB030329: Kiso B and R band observations
  74. GRB 030329: SARA Optical Observations
  75. GRB030329: final R-band light curve by MASTER
  76. GRB030329, optical observation
  77. GRB 030329, BRI photometry
  78. Further AAVSO V,B,R observations of GRB030329
  79. GRB 030329: Additional Mt. Laguna Optical Observations
  80. GRB 030329: optical observations
  81. GRB 030329, optical photometry
  82. GRB030329 - Light curve flattening
  83. GRB030329 - near contemporaneous optical limits from CONCAM
  84. GRB030329, SPM optical observations
  85. GRB 030328 Optical Observations
  86. GRB030328: Decay index
  87. Possible GRB030323 localized by INTEGRAL
  88. IPN triangulation of GRB030325 (single small error box)
  89. IPN triangulation of GRB030325 (two small error boxes)
  90. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  91. GRB 030320: Optical Observations
  92. IPN triangulation of GRB030320 (small error box)
  93. GRB030227 localized by INTEGRAL
  94. GRB030131: Optical limits for corrected position
  95. GRB 030131: afterglow candidate
  96. GRB030131: Optical limit
  97. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  98. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  99. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  100. IPN triangulation of GRB021027 (single large error box)

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