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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"

27321 results found.

  1. GRB 090424 : Multiband Optical observation from Nainital
  2. IPN triangulation of very bright GRB 090427
  3. GRB 090423: CARMA mm observations
  4. GRB 090426: Swift/BAT spectral lag results
  5. GRB 090425: Fermi GBM detection
  6. GRB 090424: Suzaku WAM observation of the prompt emission
  7. GRB 090426: VLT spectroscopy
  8. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  9. GRB 090426: Okayama MITSuME optical observation
  10. GRB 090426: Swift-BAT refined analysis
  11. GRB 090426: Swift-XRT refined analysis
  12. GRB 090423: GROND second epoch imaging and refined SED
  13. Detection of bright radio afterglow of GRB 090424 with the VLA
  14. GRB 090426: Enhanced Swift-XRT position
  15. GRB090426: Observation for Optical counterpart from MIRO
  16. GRB 090426, RIMOTS optical upper limits
  17. GRB 090426: Swift detection of a burst with an optical counterpart
  18. GRB 090424: MASTER-Net prompt optical limit
  19. GRB 090424: WHT ISIS spectroscopy
  20. VLA radio observation of high-z GRB 090423
  21. GRB 090424: THO optical observations
  22. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  23. GRB 090423: Y-band field calibration update/correction
  24. GRB 090423: Swift/BAT spectral lag results
  25. GRB 090424 : TAOS optical detection
  26. GRB 090424: Liverpool Telescope observations
  27. GRB 090424: Swift-XRT refined analysis
  28. GRB 090424: Optical observations from 1.23m CAHA
  29. GRB 090423: energetic, luminosity and jet break
  30. GRB 090424: MASTER-Net prompt optical observations
  31. GRB 090424: Enhanced Swift-XRT position
  32. GRB 090424: Swift-BAT refined analysis
  33. GRB 090423: Fermi GBM observation
  34. GRB 090424: Swift detection of a burst with an optical counterpart
  35. GRB090423: Y-band field calibration
  36. GRB 090423 limiting magnitudes
  37. GRB 090423: Near infrared observation at Okayama Observatory
  38. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  39. GRB 090423: GROND detection and preliminary photo-z
  40. GRB 090423: NOT z-band limit
  41. GRB 090423: Swift-XRT refined analysis
  42. GRB090418A Rc-band photometry
  43. GRB 090423: NIR photometry and evidence for spectral break
  44. GRB 090422: Swift-XRT refined analysis
  45. GRB090423, RIMOTS optical upper limits
  46. GRB 090423: Enhanced Swift-XRT position
  47. GRB 090423: Swift-BAT refined analysis
  48. GRB 090422: Swift/UVOT Upper Limits
  49. GRB 090423: UKIRT K-band observations
  50. GRB 090423: P60 Observations
  51. GRB 090418A: R and I band observation
  52. GRB 090423: Swift detection of a burst
  53. GRB 090422: Liverpool Telescope possible candidate
  54. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  55. GRB 090422: Swift-BAT refined analysis
  56. GRB 090422: Enhanced Swift-XRT position
  57. GRB 090418B: RTT150 optical observations
  58. GRB 080410: GAO 150cm telescope Optical Observation
  59. GRB 080408A: GAO 150cm telescope Optical Observation
  60. GRB 090422: Liverpool Telescope observations
  61. GRB 090418B: Suzaku WAM observation of the prompt emission
  62. GRB 090422: Swift detection of a burst
  63. GRB 090418C: Fermi GBM Detection
  64. GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy
  65. GRB 090418B: GRAS002 observatios
  66. GRB 090418B: GROND observations
  67. GRB 090419: Swift/UVOT Observations
  68. GRB 090418B: Faulkes Telescope North observations
  69. GRB 090418A: Swift/UVOT Observations
  70. GRB 090417B: Swift/UVOT Upper Limits
  71. GRB 090417B Correction to the BAT refined analysis position
  72. GRB 090419: Swift-XRT refined analysis
  73. Konus-Wind observation of GRB 090418B
  74. GRB 090419: GROND detection of afterglow candidate
  75. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  76. GRB 090419: Swift-BAT refined analysis
  77. VLA radio detection of GRB 090418
  78. VLA radio upper limit on GRB 090417B
  79. GRB 090419: Enhanced Swift-XRT position
  80. GRB 090418: Swift XRT refined analysis
  81. GRB 090419: Swift detection of a burst
  82. VLA observations of short burst GRB 090417A
  83. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  84. GRB 090417B: Gemini imaging
  85. GRB 090418: Swift-BAT refined analysis
  86. GRB 090417B: Swift-XRT refined analysis
  87. GRB 090418: Enhanced Swift-XRT position
  88. GRB 090418: Swift detection of a burst with optical afterglow
  89. GRB 090411B: Suzaku WAM observation of the prompt emission
  90. GRB 090411A: Suzaku WAM observation of the prompt emission
  91. GRB 090417B: Subaru NIR Observations
  92. GRB 090417B: MITSuME Okayama optical upper limits
  93. GRB 090417B: optical observations
  94. GRB090417B: optical observations
  95. GRB 090417B: Swift-BAT refined analysis
  96. GRB 090417A: Swift-BAT refined analysis
  97. GRB 090417A: Early-type nature of the putative host
  98. GRB 090417A: nearby galaxy redshift
  99. GRB 090417B: Swift detection of a burst
  100. GRB 090412: Fermi GBM detection

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