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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"

32411 results found.

  1. IPN localization of very bright long hard GRB 070207
  2. IPN localization of very intense short GRB 070201
  3. GRB 070209, Swift-BAT refined analysis of the short hard burst
  4. GRB 070209: Swift detection of a short hard burst
  5. GRB 070208: Swift XRT refined analysis
  6. GRB 070208: RAPTOR detection of early afterglow onset
  7. GRB070208: Absorption and emission redshift from Gemini
  8. GRB 070208: MDM Optical Decay
  9. GRB 070208, Swift-BAT refined analysis
  10. GRB070208 - SDSS Pre-Burst Observations
  11. GRB 070208: Early IR detection and afterglow astrometry
  12. GRB 070208: Afterglow confirmation from P60
  13. GRB070208: Faulkes Telescope North Afterglow Identification
  14. GRB 070208: ROTSE-III Optical Limits
  15. GRB 070208: MDM Observations
  16. GRB 070208: Swift detection of a burst
  17. GRB 070125 detection with CARMA
  18. Swift-BAT trigger 259527 is a Cosmic Ray Shower
  19. GRB 070125: Redshift z>~1.54 from Gemini Afterglow Spectrum
  20. GRB 070129: afterglow confirmation
  21. GRB070124: Swift-XRT Follow-up Observation
  22. GRB070126: Swift-XRT Observation
  23. GRB 070125: further AAVSO optical observations
  24. GRB 070129: Swift/UVOT Upper limits
  25. GRB 070129: dust-scattered X-ray halo detected by Swift/XRT
  26. GRB 070125: optical observation
  27. GRB 070125: WSRT Radio Detection
  28. Radio detection of GRB 070125
  29. GRB061217: MAGIC telescope GeV observation
  30. GRB 070125: confirmation of pseudo-redshift
  31. GRB 070129, Swift-BAT refined analysis of a particularly long
  32. GRB 070129: Xinglong TNT optical Upper Limit
  33. GRB 070129: Swift-XRT Refined Analysis
  34. GRB 070129: VLT observations
  35. GRB 070125: An IR Point Source and an Apparent Host Galaxy
  36. GRB 070129: Swift detection of a burst
  37. GRB 070126: Swift/UVOT refined analysis
  38. GRB 070125: further AAVSO optical observations
  39. GRB 070125: MITSuME Okayama optical observation
  40. Konus-Wind observation of GRB 070125
  41. GRB 070125: AAVSO optical observations
  42. GRB 070125: optical observations
  43. GRB 070126: VLT observations
  44. GRB070126: Swift-XRT possible detection of an afterglow
  45. GRB 070125: PROMPT detections
  46. GRB 070124: Suzaku WAM observation of the prompt emissions
  47. GRB 070125: WSRT Radio Observations
  48. GRB 070125: UVOT Detection in Ultraviolet Filters
  49. GRB 070126, Swift-BAT refined analysis of a very faint burst
  50. GRB070125: Optical observation by Kanata
  51. Possible GRB 070126: Swift/UVOT Upper Limit
  52. GRB 070125: UVOT Observations of a Fading Optical Afterglow
  53. GRB 070125: Xinglong TNT optical observations
  54. GRB 070125: Continued P60 Observations
  55. GRB 070125: pseudo-z~1.5 from spectral parameters of the prompt emission
  56. GRB 070125: Keck/LRIS Spectroscopy -- Evidence for a very low redshift
  57. GRB 070125: Lick 3m Spectroscopy
  58. GRB070125: Swift-XRT Refined Analysis
  59. GRB 070125: SARA detection in R
  60. GRB 070125: P60 Optical Afterglow Candidate
  61. GRB 070126?: Swift detection of a possible burst
  62. GRB070125 redshift request
  63. RHESSI Spectrum of GRB070125
  64. IPN-BAT localization of GRB070125 (very long duration, intense)
  65. Konus-Wind observation of short hard GRB 070124
  66. IPN localization of GRB070124 (short duration, hard spectrum)
  67. GRB 070110: optical break
  68. GRB 070110: Continued Detection and Request for Ground Followup
  69. GRB 050904: Second Epoch of HST/NICMOS Observations
  70. GRB 070110: Ep,i - Eiso correlation
  71. GRB 070107: Suzaku WAM observation of the prompt emission
  72. GRB 070110: VLT R-band photometry
  73. GRB 070110 declared a "Burst of Interest" by Swift team
  74. Further Retractions of previous Swift-BAT triggers
  75. Swift-BAT Trigger 255685 is not a GRB
  76. Trigger 255685: Swift detection of a possible burst
  77. GRB 070110: VLT absorption redshift
  78. GRB 070110: UVOT Observations of a Candidate Afterglow
  79. GRB 070110, Swift-BAT refined analysis
  80. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  81. GRB 070110: Swift detection of a burst with a possible optical afterglow
  82. IBAS Alert n. 4047: Not a GRB
  83. GRB070107: Swift/XRT refined analysis
  84. GRB 070107: Possible UVOT Afterglow
  85. GRB 070107, Swift-BAT refined analysis
  86. GRB 070107: Swift/XRT position
  87. GRB 070107: Swift detection of a burst
  88. VLA observation of GRB 061222B
  89. VLA detection of GRB 061222A
  90. GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
  91. GRB070103: KPNO 4m+FLAMINGOS J limit
  92. GRB 070103: Swift/UVOT Upper limits
  93. GRB 070103, Swift-BAT refined analysis
  94. GRB 070103: NOT observations
  95. GRB 070103: TAROT Calern observatory optical observations
  96. GRB 070103: Swift detection of a burst
  97. Retractions of previous Swift-BAT triggers
  98. GRB061222a: optical observations
  99. erratum : SDSS Pre-burst Observations of GRB061126
  100. Konus-Wind observation of GRB 061222A

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