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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').
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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"

41746 results found.

  1. GRB 041016: Optical limits
  2. GRB 041016: Optical limits in V, R, I
  3. GRB 041016:Optical limit during first minute
  4. GRB 041015: Optical Observations at Rikubetsu
  5. GRB041006: Near Infrared observations
  6. GRB 041016: Optical limit
  7. GRB 041015 R band observations
  8. GRB040924, BVRcIc field calibration
  9. GRB041015,optical observation
  10. GRB041006: Fading X-ray Afterglow Observed with Chandra
  11. GRB 041015: Optical limit at Osaka University
  12. GRB041015 : Optical follow-up at Kiso
  13. GRB 041015 - A long GRB detected by INTEGRAL
  14. GRB 041006 R observations in Loiano
  15. GRB041006: VLT observations of the afterglow and host galaxy
  16. GRB041006: Optical observations and Potential host galaxy
  17. GRB041006, BVRcIc field calibration
  18. GRB 040924: VLT spectroscopy
  19. GRB 041006: SARA afterglow observations
  20. GRB041006, optical observation in CrAO
  21. Search for SN light in XRF 040912 with MEGACAM
  22. GRB 040916: Afterglow Color at Early Times
  23. GRB 041006 Optical afterglow observations
  24. IBAS GRB Alert # 2010
  25. GRB 041006: BR observations with VATT
  26. GRB 041006: Redshift confirmed
  27. GRB041006: Liverpool Telescope optical observations
  28. GRB 041006: Colour measurement
  29. GRB041006: break in the light curve
  30. GRB 041006: Radio Observations
  31. GRB041006, further submilllimetre observations
  32. GRB 041006 : optical follow-up observation at Lulin Observatory
  33. GRB 041006 : Optical follow-up observation at TAROT
  34. GRB041006: Optical photometry and spectroscopy at TNG
  35. GRB 041006: presice astrometry
  36. GRB041006 (= H3570): Chandra Observations In Progress
  37. GRB 041006 : optical observation at Bisei
  38. GRB041006, optical I observation
  39. GRB041006 (=HETE3570): optical observations
  40. ROTSE-IIIa Observations of GRB 041006
  41. GRB041006, optical observation
  42. GRB041006, submillimetre observations
  43. GRB041006: MASTER optical observations
  44. GRB041006,optical observation
  45. GRB 041006: Optical decay
  46. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  47. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  48. GRB041006: Fading of optical afterglow candidate
  49. GRB 041006 : Optical follow-up observation at KISO
  50. GRB 041006: Finding chart
  51. GRB 041006: Optical afterglow candidate
  52. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  53. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  54. XRF 020903: Observations of the Host Galaxy (authors)
  55. XRF 020903: Observations of the Host Galaxy
  56. SGR 1806-20 still active
  57. GRB 040924: Second Epoch WSRT Radio Observations
  58. radio observations, GRB 040924
  59. GRB040929,optical observation
  60. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  61. GRB040924,optical observation
  62. GRB040924, RTT150 optical observation
  63. GRB040924,optical observation
  64. GRB 040924: detection of possible host galaxy by Subaru
  65. GRB040924, RTT150 optical observation
  66. GRB040924: KAIT observations
  67. GRB040924: Afterglow magnitude at t=17.5hr
  68. GRB 040924: WSRT Radio Observations
  69. GRB 040924: NIR finding chart
  70. GRB040924 : Optical candidate observations at Lulin observatory
  71. GRB040924 : Optical candidate observations at Lulin observatory
  72. GRB 040924: Subaru NIR observation
  73. GRB 040924: RTT150 optical observations
  74. GRB 040924, optical follow-up
  75. GRB040924: MASTER: OT decay
  76. IPN triangulation of GRB040924 (H3564)
  77. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  78. GRB040924 (H3564): Optical afterglow candidate
  79. XRF 040912: Radio Observations
  80. XRF 040916: Radio Observations
  81. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  82. XRF040916: continuing decay of OT
  83. TAROT Observations of GRB 040916 (HETE #3558)
  84. GRB040912(=H3557): Candidate Optical Afterglow
  85. XRF040916, optical observations
  86. XRF040916: Optical Transient Candidate by Subaru
  87. XRF 040912, identification of CXO sources
  88. XRF 040912 (=H3557): Spectral and Temporal Properties
  89. XRF040916, Ic observations
  90. XRF040916: optical follow-up observations
  91. XRF040912, BVRcIc field calibration
  92. XRF040916, BVRcIc field calibration
  93. GRB040916: Archival optical observations
  94. XRF 040916, optical follow-up
  95. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  96. GRB040916: Optical observations
  97. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  98. GRB040916 (= H3558): A Long XRF Localized by HETE
  99. GRB040912 (= H3557): Chandra Observations Scheduled
  100. GRB 040912: Optical Observations

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