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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"

16167 results found.

  1. GRB 041218: R-band optical observations
  2. GRB041218: Liverpool Telescope optical observations
  3. GRB041218: optical observations
  4. GRB041218: Continued P60 Optical Observations
  5. GRB 041218: Optical Observation
  6. GRB 041219: Infrared Afterglow Candidate
  7. GRB 041219: Infrared Afterglow Candidate
  8. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  9. GRB041219: P60 Optical Observations
  10. GRB041218: optical observations
  11. GRB041217: optical limit 30 min after GRB
  12. GRB 041218; optical candidate
  13. GRB 041218: Optical observations
  14. GRB 041217: LCO40 Optical Observations and Possible Candidates
  15. GRB041217: Optical Observations
  16. GRB041217: NIR and optical observations with REM
  17. GRB041217: P60 Optical Observations
  18. GRB041211: Faulkes Telescope continued optical monitoring
  19. Optical Transient in Lynx not a GRB
  20. Optical transient (GRB?) in Lynx
  21. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  22. GRB041211: Continued P60 Observations
  23. GRB041211: RAPTOR observations
  24. GRB041211: Ashra Prototype optical observation
  25. GRB041211, Faulkes Telescope optical observation
  26. GRB041211,optical observation
  27. GRB 041211: Optical follow-up in East Asian region
  28. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  29. GRB041211: P60 optical imaging
  30. GRB970815: Discovery of Optical Afterglow
  31. GRB 041006: GETS Optical Afterglow Observation
  32. GRB 041006: Optical Observations
  33. GRB041006, late-time optical photometry
  34. GRB041015, optical observation in CrAO
  35. GRB041006: RTT150 Optical Observations
  36. GRB041015 : Multi epoch optical observations
  37. GRB 041016: BOOTES-2 simultaneous observation
  38. GRB041006: RTT150 Optical Observations
  39. GRB041016,optical observation
  40. GRB 041016: Optical limits
  41. GRB 041016: Optical limits in V, R, I
  42. GRB 041016:Optical limit during first minute
  43. GRB041016: MASTER: Optical observations
  44. GRB 041015: Optical Observations at Rikubetsu
  45. GRB041006: Near Infrared observations
  46. GRB 041016: Optical limit
  47. GRB041015: MASTER: Optical observations
  48. GRB041015,optical observation
  49. GRB041006: Fading X-ray Afterglow Observed with Chandra
  50. GRB 041015: Optical limit at Osaka University
  51. GRB041015 : Optical follow-up at Kiso
  52. GRB041006: VLT observations of the afterglow and host galaxy
  53. GRB041006: Optical observations and Potential host galaxy
  54. GRB 041006: SARA afterglow observations
  55. GRB041006, optical observation in CrAO
  56. GRB 040916: Afterglow Color at Early Times
  57. GRB 041006 Optical afterglow observations
  58. GRB 041006: BR observations with VATT
  59. GRB 041006: Redshift confirmed
  60. GRB041006: Liverpool Telescope optical observations
  61. GRB041006: break in the light curve
  62. GRB 041006: Radio Observations
  63. GRB 041006 : optical follow-up observation at Lulin Observatory
  64. GRB 041006 : Optical follow-up observation at TAROT
  65. GRB041006: Optical photometry and spectroscopy at TNG
  66. GRB 041006 : optical observation at Bisei
  67. GRB041006, optical I observation
  68. GRB041006 (=HETE3570): optical observations
  69. ROTSE-IIIa Observations of GRB 041006
  70. GRB041006, optical observation
  71. GRB041006: MASTER optical observations
  72. GRB041006,optical observation
  73. GRB 041006: Optical decay
  74. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  75. GRB041006: Fading of optical afterglow candidate
  76. GRB 041006 : Optical follow-up observation at KISO
  77. GRB 041006: Finding chart
  78. GRB 041006: Optical afterglow candidate
  79. GRB 040924: Second Epoch WSRT Radio Observations
  80. radio observations, GRB 040924
  81. GRB040929,optical observation
  82. GRB040929: MASTER optical observations
  83. GRB040924,optical observation
  84. GRB040924, RTT150 optical observation
  85. GRB040924,optical observation
  86. GRB040924, RTT150 optical observation
  87. GRB040924: Afterglow magnitude at t=17.5hr
  88. GRB 040924: WSRT Radio Observations
  89. GRB040924 : Optical candidate observations at Lulin observatory
  90. GRB040924 : Optical candidate observations at Lulin observatory
  91. GRB 040924: Subaru NIR observation
  92. GRB040924: Optical afterglow properties
  93. GRB 040924: RTT150 optical observations
  94. GRB 040924, optical follow-up
  95. GRB040924: MASTER: OT decay
  96. GRB040924: MASTER Optical observations
  97. IPN triangulation of GRB040924 (H3564)
  98. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  99. GRB040924 (H3564): Optical afterglow candidate
  100. XRF 040916: Radio Observations

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