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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"
  1. GRB 070201: Correction to GCN 6094
  2. GRB 070129: MDM I-band Detection
  3. GRB 070125: Break in Optical Decay
  4. GRB 070209: Swift XRT analysis
  5. GRB 070201: clarification on localization and Konus-Wind spectra
  6. GRB070208: optical observations
  7. GRB 070201: IPN constraints and nearby galaxies
  8. GRB 070201: Proximity of IPN annulus to M31
  9. GRB 070208: MARGE Optical Observations
  10. IPN localization of very bright long hard GRB 070207
  11. IPN localization of very intense short GRB 070201
  12. GRB 070209, Swift-BAT refined analysis of the short hard burst
  13. GRB 070209: Swift detection of a short hard burst
  14. GRB 070208: Swift XRT refined analysis
  15. GRB 070208: RAPTOR detection of early afterglow onset
  16. GRB070208: Absorption and emission redshift from Gemini
  17. GRB 070208: MDM Optical Decay
  18. GRB 070208, Swift-BAT refined analysis
  19. GRB070208 - SDSS Pre-Burst Observations
  20. GRB 070208: Early IR detection and afterglow astrometry
  21. GRB 070208: Afterglow confirmation from P60
  22. GRB070208: Faulkes Telescope North Afterglow Identification
  23. GRB 070208: ROTSE-III Optical Limits
  24. GRB 070208: MDM Observations
  25. GRB 070208: Swift detection of a burst
  26. GRB 070125 detection with CARMA
  27. Swift-BAT trigger 259527 is a Cosmic Ray Shower
  28. GRB 070125: Redshift z>~1.54 from Gemini Afterglow Spectrum
  29. GRB 070129: afterglow confirmation
  30. GRB070124: Swift-XRT Follow-up Observation
  31. GRB070126: Swift-XRT Observation
  32. GRB 070125: further AAVSO optical observations
  33. GRB 070129: Swift/UVOT Upper limits
  34. GRB 070129: dust-scattered X-ray halo detected by Swift/XRT
  35. GRB 070125: optical observation
  36. GRB 070125: WSRT Radio Detection
  37. GRB070129: MITSuME optical observation
  38. Radio detection of GRB 070125
  39. GRB061217: MAGIC telescope GeV observation
  40. GRB 070125: confirmation of pseudo-redshift
  41. GRB 070129, Swift-BAT refined analysis of a particularly long
  42. GRB 070129: Xinglong TNT optical Upper Limit
  43. GRB 070129: Swift-XRT Refined Analysis
  44. GRB 070129: VLT observations
  45. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  46. GRB 070129: Swift detection of a burst
  47. GRB 070126: Swift/UVOT refined analysis
  48. GRB 070125: further AAVSO optical observations
  49. GRB 070125: MITSuME Okayama optical observation
  50. Konus-Wind observation of GRB 070125
  51. GRB 070125: AAVSO optical observations
  52. GRB 070125: optical observations
  53. GRB 070126: VLT observations
  54. GRB070126: Swift-XRT possible detection of an afterglow
  55. GRB 070125: PROMPT detections
  56. GRB 070124: Suzaku WAM observation of the prompt emissions
  57. GRB 070125: WSRT Radio Observations
  58. GRB 070125: UVOT Detection in Ultraviolet Filters
  59. GRB 070126, Swift-BAT refined analysis of a very faint burst
  60. GRB070125: Optical observation by Kanata
  61. GRB070124: Swift-XRT Observation
  62. Possible GRB 070126: Swift/UVOT Upper Limit
  63. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  64. GRB 070125: Xinglong TNT optical observations
  65. GRB 070125: Continued P60 Observations
  66. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  67. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  68. GRB 070125: Lick 3m Spectroscopy
  69. GRB070125: Swift-XRT Refined Analysis
  70. GRB 070125: SARA detection in R
  71. GRB 070125: P60 Optical Afterglow Candidate
  72. GRB 070126?: Swift detection of a possible burst
  73. GRB070125 redshift request
  74. RHESSI Spectrum of GRB070125
  75. IPN-BAT localization of GRB070125 (very long duration, intense)
  76. Konus-Wind observation of short hard GRB 070124
  77. IPN localization of GRB070124 (short duration, hard spectrum)
  78. GRB 070110: optical break
  79. Swift-BAT trigger 257213 is a Galactic Center transient
  80. GRB 070110: Continued Detection and Request for Ground Followup
  81. GRB 050904: Second Epoch of HST/NICMOS Observations
  82. GRB 070110: Ep,i - Eiso correlation
  83. GRB 070107: Suzaku WAM observation of the prompt emission
  84. GRB 070110: VLT R-band photometry
  85. GRB 070110 declared a "Burst of Interest" by Swift team
  86. Further Retractions of previous Swift-BAT triggers
  87. Swift-BAT Trigger 255685 is not a GRB
  88. Trigger 255685: Swift detection of a possible burst
  89. GRB 070110: VLT absorption redshift
  90. GRB 070110: UVOT Observations of a Candidate Afterglow
  91. GRB070110: Swift XRT Team refined analysis
  92. GRB 070110, Swift-BAT refined analysis
  93. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  94. GRB 070110: Swift detection of a burst with a possible optical afterglow
  95. IBAS Alert n. 4047: Not a GRB
  96. GRB070107: Swift/XRT refined analysis
  97. GRB 070107: Possible UVOT Afterglow
  98. GRB 070107, Swift-BAT refined analysis
  99. GRB 070107: Swift/XRT position
  100. GRB 070107: Swift detection of a burst

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