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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"

28047 results found.

  1. Second Epoch VLA observations of SGR 1806-20
  2. Second-epoch VLA observations of SGR 1806-20
  3. SGR1806 VLA Observations
  4. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  5. GRB 041217: Optical observations
  6. GRB041228: Swift-BAT detection of a burst
  7. GRB041219; RXTE ASM Observations
  8. NIR Observations of GRB 041219
  9. GRB041226: Swift-BAT detection of a burst
  10. GRB041223: decay of the afterglow
  11. GRB 041224: near-infrared observations with REM
  12. GRB 041223 Fluence measured by Swift-BAT
  13. GRB041223: optical and NIR observations with REM
  14. Swift-BAT Time History of GRB041219
  15. GRB 041219: TAROT optical observations
  16. GRB 041218: TAROT optical observations
  17. GRB 041223: J-band observations of the afterglow
  18. GRB 041219c: PROMPT Observations
  19. GRB041223: Swift-BAT detection of a bright long burst
  20. GRB 041218: optical observations
  21. GRB 041219 : optical follow-up observations
  22. Deep RAPTOR observations during GRB 041219
  23. GRB 041218 Optical Observations
  24. GRB041219: Continued NIR Observations
  25. GRB 041219 ,optical observation
  26. GRB 041219: Radio Afterglow Detection
  27. GRB 041218 : Radio Observations
  28. GRB 041218: R-band optical observations
  29. GRB041218: optical observations
  30. GRB041219: Confirmed NIR Afterglow
  31. Swift-BAT detection of the bright long burst GRB041219
  32. GRB 041219: Infrared Afterglow Candidate
  33. GRB041219, BVRcIc field calibration
  34. GRB 041219: Infrared Afterglow Candidate
  35. GRB041218, BVRcIc field calibration
  36. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  37. GRB 041219 - A long GRB detected by INTEGRAL
  38. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  39. GRB 041217: PROMPT Observations
  40. GRB 041217: LCO40 Optical Observations and Possible Candidates
  41. GRB 041218 - A long GRB detected by integral
  42. GRB041217: NIR and optical observations with REM
  43. GRB041217: Infrared Observations
  44. GRB041217: The First GRB Located On-Board Swift
  45. GRB041211: Faulkes Telescope continued optical monitoring
  46. Optical Transient in Lynx not a GRB
  47. Optical transient (GRB?) in Lynx
  48. GRB041211: RAPTOR observations
  49. GRB041211: Ashra Prototype optical observation
  50. GRB041211, BVRcIc field calibration
  51. GRB041211,optical observation
  52. GRB 041211: Infrared Observations
  53. GRB 041211: KAIT observations
  54. GRB 041211: Optical follow-up in East Asian region
  55. Triangulation of short GRB 041116 (large error box)
  56. GRB 040924: Afterglow Color
  57. GRB 041006: GETS Optical Afterglow Observation
  58. Summary of the recent bursts from SGR 1806-20
  59. GRB 041006: Optical Observations
  60. GRB041006, late-time optical photometry
  61. GRB041006: RTT150 Optical Observations
  62. HST Observations: XRF 040701 and 040812
  63. Bright bursts from SGR1806-20
  64. GRB 041016: BOOTES-2 simultaneous observation
  65. GRB041006: RTT150 Optical Observations
  66. GRB041016,optical observation
  67. GRB 041016: Optical limits
  68. GRB 041016:Optical limit during first minute
  69. GRB 041015: Optical Observations at Rikubetsu
  70. GRB 041016: Optical limit
  71. GRB 041015 R band observations
  72. GRB040924, BVRcIc field calibration
  73. GRB041015,optical observation
  74. GRB041006: Fading X-ray Afterglow Observed with Chandra
  75. GRB 041015 - A long GRB detected by INTEGRAL
  76. GRB041006: VLT observations of the afterglow and host galaxy
  77. GRB041006: Optical observations and Potential host galaxy
  78. GRB041006, BVRcIc field calibration
  79. GRB 040924: VLT spectroscopy
  80. GRB 041006: SARA afterglow observations
  81. GRB041006, optical observation in CrAO
  82. Search for SN light in XRF 040912 with MEGACAM
  83. GRB 041006: BR observations with VATT
  84. GRB 041006: Redshift confirmed
  85. GRB 041006: Radio Observations
  86. GRB 041006 : optical follow-up observation at Lulin Observatory
  87. GRB041006: Optical photometry and spectroscopy at TNG
  88. GRB 041006: presice astrometry
  89. GRB041006, optical I observation
  90. GRB041006 (=HETE3570): optical observations
  91. ROTSE-IIIa Observations of GRB 041006
  92. GRB041006: MASTER optical observations
  93. GRB041006,optical observation
  94. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  95. GRB041006: Fading of optical afterglow candidate
  96. GRB 041006: Optical afterglow candidate
  97. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  98. XRF 020903: Observations of the Host Galaxy
  99. radio observations, GRB 040924
  100. GRB040929,optical observation

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