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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"

15722 results found.

  1. GRB 041016: Optical limit
  2. GRB041015: MASTER: Optical observations
  3. GRB041015,optical observation
  4. GRB041006: Fading X-ray Afterglow Observed with Chandra
  5. GRB 041015: Optical limit at Osaka University
  6. GRB041015 : Optical follow-up at Kiso
  7. GRB041006: VLT observations of the afterglow and host galaxy
  8. GRB041006: Optical observations and Potential host galaxy
  9. GRB 041006: SARA afterglow observations
  10. GRB041006, optical observation in CrAO
  11. GRB 040916: Afterglow Color at Early Times
  12. GRB 041006 Optical afterglow observations
  13. GRB 041006: BR observations with VATT
  14. GRB 041006: Redshift confirmed
  15. GRB041006: Liverpool Telescope optical observations
  16. GRB041006: break in the light curve
  17. GRB 041006: Radio Observations
  18. GRB 041006 : optical follow-up observation at Lulin Observatory
  19. GRB 041006 : Optical follow-up observation at TAROT
  20. GRB041006: Optical photometry and spectroscopy at TNG
  21. GRB 041006 : optical observation at Bisei
  22. GRB041006, optical I observation
  23. GRB041006 (=HETE3570): optical observations
  24. ROTSE-IIIa Observations of GRB 041006
  25. GRB041006, optical observation
  26. GRB041006: MASTER optical observations
  27. GRB041006,optical observation
  28. GRB 041006: Optical decay
  29. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  30. GRB041006: Fading of optical afterglow candidate
  31. GRB 041006 : Optical follow-up observation at KISO
  32. GRB 041006: Finding chart
  33. GRB 041006: Optical afterglow candidate
  34. GRB 040924: Second Epoch WSRT Radio Observations
  35. radio observations, GRB 040924
  36. GRB040929,optical observation
  37. GRB040929: MASTER optical observations
  38. GRB040924,optical observation
  39. GRB040924, RTT150 optical observation
  40. GRB040924,optical observation
  41. GRB040924, RTT150 optical observation
  42. GRB040924: Afterglow magnitude at t=17.5hr
  43. GRB 040924: WSRT Radio Observations
  44. GRB040924 : Optical candidate observations at Lulin observatory
  45. GRB040924 : Optical candidate observations at Lulin observatory
  46. GRB 040924: Subaru NIR observation
  47. GRB040924: Optical afterglow properties
  48. GRB 040924: RTT150 optical observations
  49. GRB 040924, optical follow-up
  50. GRB040924: MASTER: OT decay
  51. GRB040924: MASTER Optical observations
  52. IPN triangulation of GRB040924 (H3564)
  53. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  54. GRB040924 (H3564): Optical afterglow candidate
  55. XRF 040916: Radio Observations
  56. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  57. XRF040916: continuing decay of OT
  58. GRB040912(=H3557): Candidate Optical Afterglow
  59. XRF040916, optical observations
  60. XRF040916: Optical Transient Candidate by Subaru
  61. GRB040916 optical limits 17 min after GRB
  62. XRF 040912, identification of CXO sources
  63. XRF 040912 (=H3557): Spectral and Temporal Properties
  64. XRF040916: optical follow-up observations
  65. GRB040916: Archival optical observations
  66. XRF 040916, optical follow-up
  67. GRB040916: Optical observations
  68. GRB040916 (= H3558): Improved Localization from HETE WXM
  69. GRB040916 (= H3558): A Long XRF Localized by HETE
  70. GRB040912 (= H3557): Chandra Observations Scheduled
  71. GRB 040912: Optical Observations
  72. GRB/XRF040912,optical observations
  73. Optical observations of GRB/XRF 040912 = HETE 3557
  74. GRB040912 : Kiso Optical follow-up observation
  75. Optical observations of field of GRB040912
  76. HETE 3557: Optical observations
  77. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  78. GRB040827: analysis of the XMM-Newton observation
  79. GRB040825A: Optical observations
  80. GRB040825A: Optical observations
  81. GRB 040827: optical and NIR observations at the VLT
  82. GRB 040827: Detection of NIR afterglow
  83. GRB 040827: Possible detection of optical afterglow
  84. GRB 040827: RTT150 optical observations
  85. GRB040825A: optical limit before GRB
  86. MASTER: GRB040827 possible OT
  87. GRB 040825B: Optical observations
  88. GRB040827 optical observations
  89. GRB 040825A,optical observations
  90. GRB040825A: optical observations
  91. GRB040825B: optical observations
  92. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  93. GRB 040825A: Optical observations.
  94. MASTER: GRB040825a optical observation
  95. MASTER: GRB040825b optical observation
  96. GRB 040825: Optical observations
  97. GRB040823,optical observation
  98. XRF 040812: optical observation at VLT
  99. GRB 040812: Optical counterparts of CXO sources
  100. CXO observation of GRB 040812

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