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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. XRF040812: possible afterglow
  2. CXO observation of GRB 040812
  3. Bursting activity from SGR 1806-20 detected with IBAS
  4. IPN/HETE localizations of GRB040810 (=H3489)
  5. GRB 040812: Keck and LCO optical observations
  6. GRB 040812: Keck and LCO observations
  7. GRB 040812: radio observations
  8. GRB040812, optical/IR observations
  9. Konus-Wind observation of GRB040810 (=H3489)
  10. GRB 040812: a long GRB detected by INTEGRAL
  11. GRB 040810: Optical observations of a limited region
  12. XRF040701: Optical Observations at ESO
  13. IPN/HETE triangulation of GRB040802 (=H3485)
  14. GRB 040730, infrared observations
  15. GRB 040730: Optical observations
  16. GRB 040730: a long GRB detected with INTEGRAL
  17. Ongoing activity of SGR 1806-20
  18. GRB040624: optical monitoring at TNG
  19. XRF 040701 - optical observations of the decaying Chandra source
  20. XRF040701: Second-Epoch Chandra Observations
  21. Cancellation of IBAS/INTEGRAL GRB alerts
  22. XRF040701: VLA Observations
  23. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  24. XRF040701: First-Epoch Chandra Observations
  25. IBAS Alert 1836: NOT a real GRB
  26. GRB040709 J,H-band observations
  27. Subject: GRB040624, optical observations
  28. GRB040706:observation at University of Miyazaki
  29. XRF 040701, optical observations
  30. XRF040701 (=U11548): a bright XRF detected by HETE
  31. GRB 040624: optical observations
  32. Optical Observations of GRB040624
  33. GRB 040624: optical observations at TNG and VLT
  34. MASTER: GRB 040624 optical observation after 0,48d
  35. GRB 040624: R-band observations
  36. GRB 040624, optical observations
  37. GRB 040624 - A long GRB detected with INTEGRAL
  38. GRB 030329: Rebrightening of hyperluminal ejecta.
  39. IPN Summary of SGR1806-20 Activity in 2004
  40. GRB040511: Retraction of redshift identification
  41. SGR 1806-20: no IR variability of the proposed counterparts
  42. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  43. SGR 1806-20, potential NIR counterpart
  44. GRB 040606: Optical observations
  45. MASTER: HETE Alert 3274 optical observation
  46. Activivty of SGR 1806-20
  47. IPN triangulation of an intense intermediate burst from SGR1806-20
  48. GRB 040511, very fast decay?
  49. GRB 030324: Detection and Color of Host Galaxy
  50. GRB 040511: NIR observations with REM
  51. GRB040511: Redshift identifcation
  52. GRB 040511: Optical limit
  53. GRB040511: Candidate optical/NIR afterglow
  54. IBAS GRB Alerts n.1785 to 1791
  55. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  56. GRB 040511: Second Epoch Optical Observations
  57. IBAS GRB Alerts 1781-4
  58. GRB 040511: Optical observations
  59. GRB 040511: Optical Observations
  60. GRB040511: Optical Observations
  61. GRB040511: Optical Observations
  62. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  63. IBAS GRB Alert number 1774: NOT a real GRB
  64. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  65. IBAS Alerts 1771 and 1772: NOT a real GRB
  66. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  67. IPN triangulation of GRB040425 (=H3183)
  68. On Line Availability of Archival HETE Fregate Data and Lightcurves
  69. GRB040422: optical observations at Xinglong Observatory
  70. GRB040422: optical observations at CrAO
  71. GRB 040423 (=H3175): A Long GRB Localized by HETE
  72. GRB040422, optical observations at Loiano
  73. GRB040422 : I-band follow-up observation at Lulin Observatory
  74. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  75. GRB040422, BVRcIc field calibration
  76. GRB 040422,optical observation
  77. GRB040422: optical and NIR observations at the VLT
  78. GRB 040422: a long GRB detected with INTEGRAL
  79. GRB 040403, deep optical observations
  80. MASTER: HETE Alert 3163, 3167 technical optical observation
  81. INTEGRAL-SPI/ACS GRB data: timing correction
  82. IBAS GRB alerts 1739, 1740, 1741
  83. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  84. GRB 040403: Optical Observations
  85. GRB 040403 Optical Observations
  86. GRB 040403: Optical observations
  87. GRB 040403: optical observations
  88. GRB 040403: Optical Observations
  89. GRB 040403: a long GRB detected with INTEGRAL
  90. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  91. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  92. IBAS GRB Alert 1694
  93. GRB040323: NIR Observations and Variable Object
  94. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  95. GRB 040323, a dark GRB ?
  96. short hard GRB 040322
  97. GRB 040323: a long GRB detected with INTEGRAL
  98. IBAS GRB alerts 1679, 1680, 1681
  99. GRB040223: Deep NIR NTT data re-analysis
  100. GRB 040223: XMM-Newton results

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