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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').
  1. GRB040924: MASTER: OT decay
  2. GRB040924: MASTER Optical observations
  3. IPN triangulation of GRB040924 (H3564)
  4. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  5. GRB040924 (H3564): Optical afterglow candidate
  6. XRF 040912: Radio Observations
  7. XRF 040916: Radio Observations
  8. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  9. XRF040916: continuing decay of OT
  10. TAROT Observations of GRB 040916 (HETE #3558)
  11. GRB040912(=H3557): Candidate Optical Afterglow
  12. XRF040916, optical observations
  13. XRF040916: Optical Transient Candidate by Subaru
  14. GRB040916 optical limits 17 min after GRB
  15. XRF 040912, identification of CXO sources
  16. XRF 040912 (=H3557): Spectral and Temporal Properties
  17. XRF040916, Ic observations
  18. XRF040916: optical follow-up observations
  19. XRF040912, BVRcIc field calibration
  20. XRF040916, BVRcIc field calibration
  21. GRB040916: Archival optical observations
  22. XRF 040916, optical follow-up
  23. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  24. GRB040916: Optical observations
  25. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  26. GRB040916 (= H3558): Improved Localization from HETE WXM
  27. GRB040916 (= H3558): A Long XRF Localized by HETE
  28. GRB040912 (= H3557): Chandra Observations Scheduled
  29. GRB 040912: Optical Observations
  30. GRB/XRF040912,optical observations
  31. GRB 040912, BVRI observations
  32. Optical observations of GRB/XRF 040912 = HETE 3557
  33. An intense burst from SGR1806-20
  34. GRB040912 : Kiso Optical follow-up observation
  35. IBAS GRB Alerts 1978-1980
  36. Optical observations of field of GRB040912
  37. HETE 3557: Optical observations
  38. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  39. GRB 040827: XMM-Newton data
  40. GRB040903 - A XRF?
  41. GRB040827: analysis of the XMM-Newton observation
  42. GRB040903, REM near-IR observation
  43. GRB 040903 - INTEGRAL data analysis
  44. IBAS Alert 1974. Not a real GRB
  45. Very bright burst detected from SGR 1806-20
  46. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  47. Possible GRB 040903 - further analysis
  48. Possible GRB 040903 detected with INTEGRAL
  49. GRB 040827 - Radio Observations
  50. XMM-Newton Images of GRB 040827
  51. GRB040825A: Optical observations
  52. GRB040825A: Optical observations
  53. GRB 040827: optical and NIR observations at the VLT
  54. GRB 040827: UKIRT - 2nd epoch K-band imaging
  55. GRB 040827: 2nd epoch of Magellan K-band imaging
  56. GRB 040827: K imaging - no evidence of variability
  57. GRB 040827: Detection of NIR afterglow
  58. GRB 040827: Possible detection of optical afterglow
  59. GRB 040827: RTT150 optical observations
  60. GRB040827 XMM-Newton observation
  61. GRB040825A: optical limit before GRB
  62. MASTER: GRB040827 possible OT
  63. GRB 040825B: Optical observations
  64. GRB040827 optical observations
  65. GRB 040827 : Planned XMM-Newton observation
  66. GRB 040827 - Refined position
  67. GRB 040827 : peak flux
  68. GRB 040827 - A long GRB detected by INTEGRAL
  69. GRB040825B, BVRcIc field photometry
  70. GRB040825A, BVRcIc field photometry
  71. GCN GRB OBSERBATION REPORT
  72. GRB 040825A,optical observations
  73. Increase of SGR 1806-20 activity
  74. GRB040825A: optical observations
  75. GRB040825B: optical observations
  76. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  77. GRB 040825A: Optical observations.
  78. MASTER: GRB040825a optical observation
  79. MASTER: GRB040825b optical observation
  80. GRB040825B: Correction to GCN 2657
  81. GRB 040825: Optical observations
  82. XRF040812: possible afterglow second Chandra observation
  83. GRB 040812: Second epoch CXO Observations
  84. GRB040823,optical observation
  85. XRF040812: GMRT observations
  86. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  87. XRF 040812: optical observation at VLT
  88. GRB 040812: Optical counterparts of CXO sources
  89. XRF040812: possible afterglow
  90. CXO observation of GRB 040812
  91. Bursting activity from SGR 1806-20 detected with IBAS
  92. IPN/HETE localizations of GRB040810 (=H3489)
  93. GRB 040812: Keck and LCO optical observations
  94. GRB 040812: Keck and LCO observations
  95. GRB 040812: radio observations
  96. GRB040812, optical/IR observations
  97. Konus-Wind observation of GRB040810 (=H3489)
  98. GRB 040812: a long GRB detected by INTEGRAL
  99. GRB 040810: Optical observations of a limited region
  100. XRF040701: Optical Observations at ESO

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