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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"

27560 results found.

  1. Fermi LAT detection of GRB 090510
  2. GRB 090509, SMARTS optical/IR afterglow observations
  3. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  4. GRB 090510: Swift detection of a short hard burst
  5. GRB 090418A: optical observation
  6. GRB 090509: GROND further analysis and redshift limit
  7. GRB 090509: REM NIR afterglow
  8. GRB 090509: GROND afterglow candidate
  9. GRB 090509: Swift detection of a burst
  10. GRB 090323: optical observations
  11. GRB 090423: optical limit
  12. GRB 090423: 250 GHz upper limit for a z=8.2 GRB with MAMBO-2 at the IRAM 30m
  13. GRB 080913: 250 GHz upper limit for a z=6.7 GRB with MAMBO-2 at the IRAM 30m
  14. GRB 090424: optical observations
  15. GRB 090429A: ROVOR magnitude limit
  16. GRB 090424, SMARTS optical/IR afterglow monitoring
  17. GRB 090426: optical observations
  18. GRB 090429D: Fermi GBM detection
  19. GRB 090429C: Fermi GBM detection
  20. GRB 090429B: Swift/UVOT Upper Limits
  21. GRB 090429A: Swift/UVOT Upper Limits
  22. GRB 090429B: Gemini-N further nIR observations
  23. GRB 090429A: Swift-XRT refined analysis
  24. GRB 090429A: GROND upper limits
  25. GRB 090427C: Fermi GBM detection
  26. GRB 090427B: Fermi GBM detection
  27. GRB 090426C: Fermi GBM detection
  28. GRB 090426B: Fermi GBM detection/observation
  29. GRB 090429B: Swift XRT refined analysis
  30. GRB 090429A: Enhanced Swift-XRT position
  31. GRB 090428B: Fermi GBM detection
  32. GRB 090428: Fermi GBM detection
  33. GRB 090418A BVRcIc field calibration
  34. GRB 090429B: Enhanced Swift-XRT position
  35. GRB 090429A - Correction to XRT position
  36. GRB090429B: Gemini-N infrared IR candidate
  37. GRB 090429B: VLT upper limits
  38. GRB 090429B: GROND Observations
  39. GRB 090429B: Super-LOTIS early observations
  40. GRB 090429B: Swift detection of a burst
  41. GRB 090429: Swift detection of a burst
  42. GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
  43. GRB 090424 : Multiband Optical observation from Nainital
  44. GRB 090426: R-band limit
  45. GRB 090424: Continued R-band monitoring
  46. GRB 090423: CARMA mm observations
  47. GRB 090423: millimeter detection
  48. GRB 090425: Fermi GBM detection
  49. GRB 090426: VLT spectroscopy
  50. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  51. GRB 090426: Near infrared observation with ISLE at OAO
  52. GRB 090426: Okayama MITSuME optical observation
  53. GRB090426 Swift/UVOT observations
  54. GRB 090426 Keck LRIS redshift
  55. GRB 090426: Swift-XRT refined analysis
  56. GRB 090423: GROND second epoch imaging and refined SED
  57. Detection of bright radio afterglow of GRB 090424 with the VLA
  58. GRB 090426: Enhanced Swift-XRT position
  59. GRB090426: Observation for Optical counterpart from MIRO
  60. GRB 090426: inspection of SDSS images
  61. GRB 090426: Swift detection of a burst with an optical counterpart
  62. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  63. GRB 090424: MASTER-Net prompt optical limit
  64. GRB 090424: WHT ISIS spectroscopy
  65. VLA radio observation of high-z GRB 090423
  66. GRB090424: BVRI/R-band detection after 15 hrs burst
  67. GRB 090424 : Lulin 1m telescope optical observations
  68. GRB 090424: THO optical observations
  69. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  70. GRB090423: Y-band limit
  71. GRB 090424 Gemini-South Redshift
  72. GRB 090424 : TAOS optical detection
  73. GRB 090424 optical observations
  74. GRB 090424: Liverpool Telescope observations
  75. GRB 090424: Swift-XRT refined analysis
  76. GRB 090424: Optical observations from 1.23m CAHA
  77. GRB 090423: energetic, luminosity and jet break
  78. Swift/UVOT observations of GRB 090424
  79. GRB 090424: Enhanced Swift-XRT position
  80. GRB 090424: TNT optical observations
  81. GRB 090424: Swift detection of a burst with an optical counterpart
  82. GRB 090423: Refined TNG analysis
  83. GRB 090423 limiting magnitudes
  84. GRB 090423: VLT/ISAAC spectroscopy
  85. GRB 090423: Near infrared observation at Okayama Observatory
  86. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  87. GRB 090423: TNG Amici spectrum
  88. GRB 090423: GROND detection and preliminary photo-z
  89. GRB 090423: NOT z-band limit
  90. GRB 090423: Correction to NIR photometry
  91. GRB 090423: Swift-XRT refined analysis
  92. GRB090418A Rc-band photometry
  93. GRB090423 - Swift/UVOT upper limits.
  94. GRB 090423: NIR photometry and evidence for spectral break
  95. GRB 090422: Swift-XRT refined analysis
  96. GRB 090423: UKIRT data further analysis
  97. GRB 090423: Enhanced Swift-XRT position
  98. GRB 090422: Swift/UVOT Upper Limits
  99. GRB 090423: UKIRT K-band observations
  100. GRB 090423: P60 Observations

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