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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"

20537 results found.

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

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