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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"

15985 results found.

  1. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  2. GRB050117: optical observation
  3. GRB 050117: Optical observation
  4. GRB050117: MASTER optical observations
  5. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  6. SGR 1806-20 and extragalactic short-duration GRBs
  7. GRB 041217: Optical observations
  8. GRB041219, early time observations
  9. GRB041228: ROTSE-III Optical Observations
  10. GRB041226: ROTSE-III Optical Observations
  11. GRB041223: decay of the afterglow
  12. GRB041224: ROTSE-III Optical Observations
  13. GRB 041224: near-infrared observations with REM
  14. GRB 041223: XRT afterglow spectrum and light curve
  15. GRB041223: optical and NIR observations with REM
  16. Swift-BAT Time History of GRB041219
  17. GRB 041219: TAROT optical observations
  18. GRB 041218: TAROT optical observations
  19. GRB 041223: Detection of Optical Transient with LCO40
  20. GRB041223: ROTSE-III Optical Observations
  21. GRB 041218: optical observations
  22. GRB 041218: Optical observations
  23. GRB 041219 : optical follow-up observations
  24. Deep RAPTOR observations during GRB 041219
  25. GRB 041218 Optical Observations
  26. GRB 041219 Optical Observations
  27. GRB041219: Optical Afterglow Detection
  28. GRB 041219 ,optical observation
  29. GRB 041219: Radio Afterglow Detection
  30. GRB 041218 : Radio Observations
  31. GRB 041218: R-band optical observations
  32. GRB041218: Liverpool Telescope optical observations
  33. GRB041218: optical observations
  34. GRB041218: Continued P60 Optical Observations
  35. GRB 041218: Optical Observation
  36. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  37. GRB041219: P60 Optical Observations
  38. GRB041218: optical observations
  39. GRB041217: optical limit 30 min after GRB
  40. GRB 041218; optical candidate
  41. GRB 041218: Optical observations
  42. GRB 041217: LCO40 Optical Observations and Possible Candidates
  43. GRB041217: Optical Observations
  44. GRB041217: NIR and optical observations with REM
  45. GRB041217: P60 Optical Observations
  46. GRB041211: Faulkes Telescope continued optical monitoring
  47. Optical Transient in Lynx not a GRB
  48. Optical transient (GRB?) in Lynx
  49. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  50. GRB041211: RAPTOR observations
  51. GRB041211: Ashra Prototype optical observation
  52. GRB041211, Faulkes Telescope optical observation
  53. GRB041211,optical observation
  54. GRB 041211: Infrared Observations
  55. GRB 041211: Optical follow-up in East Asian region
  56. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  57. GRB041211: P60 optical imaging
  58. GRB970815: Discovery of Optical Afterglow
  59. GRB 041006: GETS Optical Afterglow Observation
  60. GRB 041006: Optical Observations
  61. GRB041006, late-time optical photometry
  62. GRB041015, optical observation in CrAO
  63. GRB041006: RTT150 Optical Observations
  64. GRB041015 : Multi epoch optical observations
  65. GRB 041016: BOOTES-2 simultaneous observation
  66. GRB041006: RTT150 Optical Observations
  67. GRB041016,optical observation
  68. GRB 041016: Optical limits
  69. GRB 041016: Optical limits in V, R, I
  70. GRB 041016:Optical limit during first minute
  71. GRB041016: MASTER: Optical observations
  72. GRB 041015: Optical Observations at Rikubetsu
  73. GRB041006: Near Infrared observations
  74. GRB 041016: Optical limit
  75. GRB041015: MASTER: Optical observations
  76. GRB041015,optical observation
  77. GRB041006: Fading X-ray Afterglow Observed with Chandra
  78. GRB 041015: Optical limit at Osaka University
  79. GRB041015 : Optical follow-up at Kiso
  80. GRB041006: VLT observations of the afterglow and host galaxy
  81. GRB041006: Optical observations and Potential host galaxy
  82. GRB 041006: SARA afterglow observations
  83. GRB041006, optical observation in CrAO
  84. GRB 040916: Afterglow Color at Early Times
  85. GRB 041006 Optical afterglow observations
  86. GRB 041006: BR observations with VATT
  87. GRB 041006: Redshift confirmed
  88. GRB041006: Liverpool Telescope optical observations
  89. GRB041006: break in the light curve
  90. GRB 041006: Radio Observations
  91. GRB 041006 : optical follow-up observation at Lulin Observatory
  92. GRB 041006 : Optical follow-up observation at TAROT
  93. GRB041006: Optical photometry and spectroscopy at TNG
  94. GRB 041006 : optical observation at Bisei
  95. GRB041006, optical I observation
  96. GRB041006 (=HETE3570): optical observations
  97. ROTSE-IIIa Observations of GRB 041006
  98. GRB041006, optical observation
  99. GRB041006: MASTER optical observations
  100. GRB041006,optical observation

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