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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"

20547 results found.

  1. GRB 050607, radio observations
  2. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  3. GRB 050525A: Swift Late-Time Decay Rate
  4. GRB050525a: HST Observations
  5. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  6. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  7. XRF 050509c: Optical monitoring
  8. XRF050509c: Radio Detection
  9. GRB 050416(a): Host Galaxy Redshift Determination
  10. GRB 050607: MDM Observation
  11. GRB 050607 optical decay
  12. GRB 050607: RTT150 optical observations
  13. GRB050607: refined analysis of prompt REM observations
  14. Swift/UVOT observations of GRB050607
  15. GRB 050607 : Lulin R-band observation
  16. GRB 050607: PROMPT VRcIc Observations
  17. GRB 050607: RAPTOR-S Early Optical Limits
  18. GRB 050525a, Mid-Infrared Observations
  19. GRB 050607: Optical decay and spectral slope
  20. GRB 050607: MDM Observations
  21. GRB 050607 - XRT refined data analysis
  22. Optical Afterglow of GRB 050607
  23. GRB050607: P60 Observations
  24. GRB050607: prompt REM observations
  25. GRB 050603: prediction of t_break
  26. GRB 050603 - XRT data analysis of the first day
  27. GRB 050603: Analysis of UVOT data
  28. GRB050603: Fading Afterglow observed by Swift UVOT
  29. GRB050603, submillimetre observations
  30. GRB 050603: Swift XRT Position
  31. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  32. Swift/BAT Detection of GRB050603
  33. GRB 050408: jet break in the XRT light curve
  34. GRB 050525a, infrared observations
  35. GRB 050525a, SMARTS optical/IR afterglow observations
  36. GRB050528, XRT observations
  37. GRB050528: updated Liverpool Telescope limits
  38. Possible GRB050528: no candidate from Liverpool Telescope
  39. GRB050525a: Radio Observations
  40. GRB 050509b: refined XRT/Chandra afterglow position analysis
  41. GRB 050525: RTT150, Optical observations
  42. GRB 050525a: SARA Observations
  43. GRB 050525B: Swift-BAT observations
  44. GRB 050525a: MDM Observations
  45. GRB 050525 : Lulin optical afterglow observations
  46. GRB050525: Super-LOTIS observations
  47. GRB 050525a: Gemini/GMOS Spectra
  48. GRB050306: optical afterglow not confirmed
  49. GRB 050525A: BOOTES simultaneous optical observations
  50. GRB050525: Optical observations
  51. GRB 050525: TAROT observations of the early afterglow
  52. GRB 050525, infrared observations
  53. GRB 050525: observatons of the optical afterglow
  54. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  55. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  56. XRF050522: NIR observations of XRT candidate
  57. XRF 050522: Swift XRT refined analysis
  58. XRF050522: Radio Observations
  59. XRF 050522: Continued NIR P200 Monitoring
  60. RBO Observations of GRB050522
  61. GRB050509b: optical observations
  62. GRB050520: Radio Observations
  63. XRF 050522: Swift XRT observation
  64. XRF050522, BVRcIc field photometry
  65. XRF 050522 : Lulin observations
  66. XRF050522: Optical Observations
  67. XRF050522: Near-infrared Observations
  68. XRF 050522: KAIT observations
  69. GRB 050520: VLT/ULTRACAM observations
  70. Swift UVOT Observations of GRB 050520
  71. XRF 050509c: Swift XRT Upper Limit
  72. XRF050509c: Radio Observations
  73. RBO Observations of GRB050520
  74. GRB 050520: P200 Observations
  75. RBO Observations of GRB050520
  76. GRB 050520: TAROT optical limit
  77. GRB 050520: Swift XRT position
  78. GRB 050520: VLT/ULTRACAM observations
  79. GRB 050520: OSN optical observations
  80. GRB 050504: Swift XRT afterglow candidate has faded
  81. XRF 050509c optical afterglow
  82. GRB 050509B and short GRB-SN association? (corrected)
  83. GRB 050509B and short GRB-SN association?
  84. GRB 050509B: Subaru Optical Observations
  85. GRB050509b, Bok telescope B-band imaging
  86. GRB050509b, SDSS pre-burst observations
  87. GRB 050509b: Keck/Chandra Cross-Correlation
  88. Chandra observation of GRB 050509b
  89. GRB050509B: Optical/Infared observations
  90. GRB 050509b Milagro GeV/TeV Observations
  91. GRB050509B: Optical observations at the Very Large Telescope
  92. GRB 050509b: No Optical Variability in XRT Error Circle
  93. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  94. GRB 050509B: WSRT Radio Observations
  95. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  96. GRB 050505, early TAROT observation
  97. GRB 050509b: Further Analysis of Keck LRIS Images
  98. GRB050509c: REM NIR and Optical observations
  99. GRB 050509b: Physical Properties of the Candidate Host galaxy
  100. GRB 050505: SARA Observations

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