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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"

20540 results found.

  1. GRB041219: Optical Afterglow Detection
  2. GRB041219: Continued NIR Observations
  3. GRB 041219: Radio Afterglow Detection
  4. GRB 041218 : Radio Observations
  5. GRB 041218: R-band optical observations
  6. GRB041218: Liverpool Telescope optical observations
  7. GRB041218: optical observations
  8. GRB041218: Continued P60 Optical Observations
  9. GRB 041219: Infrared Afterglow Candidate
  10. GRB 041219: Infrared Afterglow Candidate
  11. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  12. GRB041219: P60 Optical Observations
  13. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  14. GRB 041217: PROMPT Observations
  15. GRB041218: optical observations
  16. GRB 041218; optical candidate
  17. GRB 041218: Optical observations
  18. GRB 041217: LCO40 Optical Observations and Possible Candidates
  19. GRB041217: Optical Observations
  20. GRB041217: NIR and optical observations with REM
  21. GRB041217: P60 Optical Observations
  22. GRB041217: Infrared Observations
  23. GRB041211: Faulkes Telescope continued optical monitoring
  24. Optical transient (GRB?) in Lynx
  25. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  26. GRB041211: Continued P60 Observations
  27. GRB041211: RAPTOR observations
  28. GRB041211, Faulkes Telescope optical observation
  29. GRB 041211: Infrared Observations
  30. GRB 041211: KAIT observations
  31. GRB 041211: Optical follow-up in East Asian region
  32. GRB970815: Discovery of Optical Afterglow
  33. GRB041015: Near-Infrared observations
  34. GRB 040924: Afterglow Color
  35. GRB 041006: Optical Observations
  36. GRB041006, late-time optical photometry
  37. GRB041006: RTT150 Optical Observations
  38. GRB041015 : Multi epoch optical observations
  39. HST Observations: XRF 040701 and 040812
  40. GRB041006: RTT150 Optical Observations
  41. GRB 041016:Optical limit during first minute
  42. GRB041016: MASTER: Optical observations
  43. GRB 041015: Optical Observations at Rikubetsu
  44. GRB041006: Near Infrared observations
  45. GRB 041015 R band observations
  46. GRB041015: MASTER: Optical observations
  47. GRB041006: Fading X-ray Afterglow Observed with Chandra
  48. GRB 041006 R observations in Loiano
  49. GRB041006: VLT observations of the afterglow and host galaxy
  50. GRB041006: Optical observations and Potential host galaxy
  51. GRB 040924: VLT spectroscopy
  52. GRB 041006: SARA afterglow observations
  53. Search for SN light in XRF 040912 with MEGACAM
  54. GRB 040916: Afterglow Color at Early Times
  55. GRB 041006 Optical afterglow observations
  56. IBAS GRB Alert # 2010
  57. GRB 041006: BR observations with VATT
  58. GRB 041006: Redshift confirmed
  59. GRB041006: Liverpool Telescope optical observations
  60. GRB 041006: Colour measurement
  61. GRB 041006: Radio Observations
  62. GRB041006, further submilllimetre observations
  63. GRB041006: Optical photometry and spectroscopy at TNG
  64. GRB041006 (= H3570): Chandra Observations In Progress
  65. GRB041006, optical I observation
  66. GRB041006 (=HETE3570): optical observations
  67. ROTSE-IIIa Observations of GRB 041006
  68. GRB041006, submillimetre observations
  69. GRB041006: MASTER optical observations
  70. GRB 041006: Optical decay
  71. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  72. XRF 020903: Observations of the Host Galaxy (authors)
  73. XRF 020903: Observations of the Host Galaxy
  74. SGR 1806-20 still active
  75. GRB 040924: Second Epoch WSRT Radio Observations
  76. radio observations, GRB 040924
  77. GRB040929: MASTER optical observations
  78. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  79. GRB040924,optical observation
  80. GRB040924, RTT150 optical observation
  81. GRB 040924: detection of possible host galaxy by Subaru
  82. GRB040924, RTT150 optical observation
  83. GRB040924: KAIT observations
  84. GRB 040924: WSRT Radio Observations
  85. GRB040924 : Optical candidate observations at Lulin observatory
  86. GRB040924 : Optical candidate observations at Lulin observatory
  87. GRB040924: Optical afterglow properties
  88. GRB 040924: RTT150 optical observations
  89. GRB040924: MASTER Optical observations
  90. GRB040924 (H3564): Optical afterglow candidate
  91. XRF 040912: Radio Observations
  92. XRF 040916: Radio Observations
  93. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  94. XRF040916: continuing decay of OT
  95. TAROT Observations of GRB 040916 (HETE #3558)
  96. XRF040916, optical observations
  97. XRF 040912, identification of CXO sources
  98. XRF040916, Ic observations
  99. XRF040916: optical follow-up observations
  100. GRB040916: Archival optical observations

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