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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"

25050 results found.

  1. GRB 050525a: PROMPT VRcIc Detections
  2. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  3. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  4. GRB 050626: Swift XRT observations
  5. GRB 050701
  6. GRB 050701, optical observations
  7. GRB 050408: ARC 3.5-meter NIR Observations
  8. GRB 050701: Refined XRT analysis
  9. Swift UVOT observations of GRB 050701
  10. GRB 050607, radio observations
  11. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  12. GRB 050626 - a long GRB detected with INTEGRAL
  13. GRB050525a: HST Observations
  14. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  15. XRF 050509c: Optical monitoring
  16. XRF050509c: Radio Detection
  17. GRB 050416(a): Host Galaxy Redshift Determination
  18. GRB 050607 optical decay
  19. GRB050607: refined analysis of prompt REM observations
  20. GRB 050607: PROMPT VRcIc Observations
  21. GRB 050525a, Mid-Infrared Observations
  22. GRB 050607: Optical decay and spectral slope
  23. GRB 050607: MDM Observations
  24. GRB050607,optical observation
  25. GRB 050607 - XRT refined data analysis
  26. Optical Afterglow of GRB 050607
  27. GRB050607: Swift Detection of a long GRB
  28. GRB050607: prompt REM observations
  29. Limits on a SN in the field of GRB 050509b
  30. GRB 050603: Redshift
  31. GRB050603, submillimetre observations
  32. GRB 050603: Swift XRT Position
  33. GRB050603: Radio Detection
  34. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  35. GRB 050603: INTEGRAL shows it is not a short GRB
  36. GRB 050525a, infrared observations
  37. GRB050528, XRT observations
  38. GRB050528: updated Liverpool Telescope limits
  39. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  40. Possible GRB050528: no candidate from Liverpool Telescope
  41. GRB050525a: Radio Observations
  42. GRB 050509b: refined XRT/Chandra afterglow position analysis
  43. GRB 050525: RTT150, Optical observations
  44. GRB 050525a: SARA Observations
  45. GRB 050525B: Swift-BAT observations
  46. GRB 050525: MITSuME Optical Observation in VRI
  47. GRB050525A,optical observation
  48. GRB050525: Super-LOTIS observations
  49. GRB 050525, spectral lag pseudo-redshift
  50. GRB050306: optical afterglow not confirmed
  51. GRB 050525: BART optical observation
  52. GRB 050525A: BOOTES simultaneous optical observations
  53. GRB 050525A: Swift-BAT refined analysis
  54. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  55. GRB 050525: TAROT observations of the early afterglow
  56. INTEGRAL detection of GRB 050525
  57. GRB 050525, infrared observations
  58. GRB 050525: observatons of the optical afterglow
  59. GRB050525: ROTSE-III Refined Analysis
  60. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  61. XRF050522: Radio Observations
  62. Swift/UVOT observation of XRF 050522
  63. GRB 050509A: Further I-band imaging
  64. GRB050522,optical observation
  65. GRB050520,optical observation
  66. XRF 050522: Continued NIR P200 Monitoring
  67. RBO Observations of GRB050522
  68. Recent GRB BVRcIc field photometry
  69. GRB050520: Radio Observations
  70. XRF 050522: Swift XRT observation
  71. XRF050522, BVRcIc field photometry
  72. XRF050522: Optical Observations
  73. XRF050522: Near-infrared Observations
  74. GRB 050520: VLT/ULTRACAM observations
  75. GRB 050520: Swift XRT refined analysis
  76. XRF050509C: Chandra Afterglow Detection
  77. XRF 050509c: Swift XRT Upper Limit
  78. XRF050509c: Radio Observations
  79. GRB 050520: P200 Observations
  80. GRB050520: Liverpool Telescope follow-up
  81. GRB 050520: TAROT optical limit
  82. GRB 050520: VLT/ULTRACAM observations
  83. GRB 050509B and short GRB-SN association? (corrected)
  84. GRB 050509B and short GRB-SN association?
  85. GRB050502b: Early Observation
  86. GRB050509b, Bok telescope B-band imaging
  87. Refined Chandra analysis of GRB 050509b
  88. GRB050509b, SDSS pre-burst observations
  89. GRB 050509b: Keck/Chandra Cross-Correlation
  90. GRB 050509b: Keck/Chandra Cross-Correlation
  91. Chandra observation of GRB 050509b
  92. GRB 050509b Milagro GeV/TeV Observations
  93. GRB050509B: Optical observations at the Very Large Telescope
  94. GRB 050509b: No Optical Variability in XRT Error Circle
  95. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  96. GRB 050509c: ROTSE-III Optical Limits
  97. GRB 050505, early TAROT observation
  98. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  99. GRB050509c: REM NIR and Optical observations
  100. GRB 050505: SARA Observations

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