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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 060927: PROMPT Observations
  2. GRB 070201: Correction to GCN 6094
  3. GRB 070129: MDM I-band Detection
  4. GRB 070125: Break in Optical Decay
  5. GRB 070209: Swift XRT analysis
  6. GRB 070201: clarification on localization and Konus-Wind spectra
  7. GRB070208: optical observations
  8. GRB 070201: IPN constraints and nearby galaxies
  9. GRB 070201: Proximity of IPN annulus to M31
  10. GRB 070208: MARGE Optical Observations
  11. IPN localization of very bright long hard GRB 070207
  12. IPN localization of very intense short GRB 070201
  13. GRB 070209, Swift-BAT refined analysis of the short hard burst
  14. GRB 070209: Swift detection of a short hard burst
  15. GRB 070208: Swift XRT refined analysis
  16. GRB 070208: RAPTOR detection of early afterglow onset
  17. GRB070208: Absorption and emission redshift from Gemini
  18. GRB 070208: MDM Optical Decay
  19. GRB 070208, Swift-BAT refined analysis
  20. GRB070208 - SDSS Pre-Burst Observations
  21. GRB 070208: Early IR detection and afterglow astrometry
  22. GRB 070208: Afterglow confirmation from P60
  23. GRB070208: Faulkes Telescope North Afterglow Identification
  24. GRB 070208: ROTSE-III Optical Limits
  25. GRB 070208: MDM Observations
  26. GRB 070208: Swift detection of a burst
  27. GRB 070125 detection with CARMA
  28. Swift-BAT trigger 259527 is a Cosmic Ray Shower
  29. GRB 070125: Redshift z>~1.54 from Gemini Afterglow Spectrum
  30. GRB 070129: afterglow confirmation
  31. GRB070124: Swift-XRT Follow-up Observation
  32. GRB070126: Swift-XRT Observation
  33. GRB 070125: further AAVSO optical observations
  34. GRB 070129: Swift/UVOT Upper limits
  35. GRB 070129: dust-scattered X-ray halo detected by Swift/XRT
  36. GRB 070125: optical observation
  37. GRB 070125: WSRT Radio Detection
  38. GRB070129: MITSuME optical observation
  39. Radio detection of GRB 070125
  40. GRB061217: MAGIC telescope GeV observation
  41. GRB 070125: confirmation of pseudo-redshift
  42. GRB 070129, Swift-BAT refined analysis of a particularly long
  43. GRB 070129: Xinglong TNT optical Upper Limit
  44. GRB 070129: Swift-XRT Refined Analysis
  45. GRB 070129: VLT observations
  46. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  47. GRB 070129: Swift detection of a burst
  48. GRB 070126: Swift/UVOT refined analysis
  49. GRB 070125: further AAVSO optical observations
  50. GRB 070125: MITSuME Okayama optical observation
  51. Konus-Wind observation of GRB 070125
  52. GRB 070125: AAVSO optical observations
  53. GRB 070125: optical observations
  54. GRB 070126: VLT observations
  55. GRB070126: Swift-XRT possible detection of an afterglow
  56. GRB 070125: PROMPT detections
  57. GRB 070124: Suzaku WAM observation of the prompt emissions
  58. GRB 070125: WSRT Radio Observations
  59. GRB 070125: UVOT Detection in Ultraviolet Filters
  60. GRB 070126, Swift-BAT refined analysis of a very faint burst
  61. GRB070125: Optical observation by Kanata
  62. GRB070124: Swift-XRT Observation
  63. Possible GRB 070126: Swift/UVOT Upper Limit
  64. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  65. GRB 070125: Xinglong TNT optical observations
  66. GRB 070125: Continued P60 Observations
  67. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  68. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  69. GRB 070125: Lick 3m Spectroscopy
  70. GRB070125: Swift-XRT Refined Analysis
  71. GRB 070125: SARA detection in R
  72. GRB 070125: P60 Optical Afterglow Candidate
  73. GRB 070126?: Swift detection of a possible burst
  74. GRB070125 redshift request
  75. RHESSI Spectrum of GRB070125
  76. IPN-BAT localization of GRB070125 (very long duration, intense)
  77. Konus-Wind observation of short hard GRB 070124
  78. IPN localization of GRB070124 (short duration, hard spectrum)
  79. GRB 070110: optical break
  80. Swift-BAT trigger 257213 is a Galactic Center transient
  81. GRB 070110: Continued Detection and Request for Ground Followup
  82. GRB 050904: Second Epoch of HST/NICMOS Observations
  83. GRB 070110: Ep,i - Eiso correlation
  84. GRB 070107: Suzaku WAM observation of the prompt emission
  85. GRB 070110: VLT R-band photometry
  86. GRB 070110 declared a "Burst of Interest" by Swift team
  87. Further Retractions of previous Swift-BAT triggers
  88. Swift-BAT Trigger 255685 is not a GRB
  89. Trigger 255685: Swift detection of a possible burst
  90. GRB 070110: VLT absorption redshift
  91. GRB 070110: UVOT Observations of a Candidate Afterglow
  92. GRB070110: Swift XRT Team refined analysis
  93. GRB 070110, Swift-BAT refined analysis
  94. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  95. GRB 070110: Swift detection of a burst with a possible optical afterglow
  96. IBAS Alert n. 4047: Not a GRB
  97. GRB070107: Swift/XRT refined analysis
  98. GRB 070107: Possible UVOT Afterglow
  99. GRB 070107, Swift-BAT refined analysis
  100. GRB 070107: Swift/XRT position

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