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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. GRB 040812: Keck and LCO observations
  2. GRB 040812: radio observations
  3. GRB040812, optical/IR observations
  4. Konus-Wind observation of GRB040810 (=H3489)
  5. GRB 040812: a long GRB detected by INTEGRAL
  6. GRB 040810: Optical observations of a limited region
  7. XRF040701: Optical Observations at ESO
  8. IPN/HETE triangulation of GRB040802 (=H3485)
  9. GRB 040730, infrared observations
  10. GRB 040730: Optical observations
  11. GRB 040730: a long GRB detected with INTEGRAL
  12. Ongoing activity of SGR 1806-20
  13. GRB040624: optical monitoring at TNG
  14. XRF 040701 - optical observations of the decaying Chandra source
  15. XRF040701: Second-Epoch Chandra Observations
  16. Cancellation of IBAS/INTEGRAL GRB alerts
  17. XRF040701: VLA Observations
  18. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  19. XRF040701: First-Epoch Chandra Observations
  20. IBAS Alert 1836: NOT a real GRB
  21. GRB040709 J,H-band observations
  22. Subject: GRB040624, optical observations
  23. GRB040706:observation at University of Miyazaki
  24. XRF 040701, optical observations
  25. XRF040701 (=U11548): a bright XRF detected by HETE
  26. GRB 040624: optical observations
  27. Optical Observations of GRB040624
  28. GRB 040624: optical observations at TNG and VLT
  29. MASTER: GRB 040624 optical observation after 0,48d
  30. GRB 040624: R-band observations
  31. GRB 040624, optical observations
  32. GRB 040624 - A long GRB detected with INTEGRAL
  33. GRB 030329: Rebrightening of hyperluminal ejecta.
  34. IPN Summary of SGR1806-20 Activity in 2004
  35. GRB040511: Retraction of redshift identification
  36. SGR 1806-20: no IR variability of the proposed counterparts
  37. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  38. SGR 1806-20, potential NIR counterpart
  39. GRB 040606: Optical observations
  40. MASTER: HETE Alert 3274 optical observation
  41. Activivty of SGR 1806-20
  42. IPN triangulation of an intense intermediate burst from SGR1806-20
  43. GRB 040511, very fast decay?
  44. GRB 030324: Detection and Color of Host Galaxy
  45. GRB 040511: NIR observations with REM
  46. GRB040511: Redshift identifcation
  47. GRB 040511: Optical limit
  48. GRB040511: Candidate optical/NIR afterglow
  49. IBAS GRB Alerts n.1785 to 1791
  50. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  51. GRB 040511: Second Epoch Optical Observations
  52. IBAS GRB Alerts 1781-4
  53. GRB 040511: Optical observations
  54. GRB 040511: Optical Observations
  55. GRB040511: Optical Observations
  56. GRB040511: Optical Observations
  57. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  58. IBAS GRB Alert number 1774: NOT a real GRB
  59. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  60. IBAS Alerts 1771 and 1772: NOT a real GRB
  61. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  62. IPN triangulation of GRB040425 (=H3183)
  63. On Line Availability of Archival HETE Fregate Data and Lightcurves
  64. GRB040422: optical observations at Xinglong Observatory
  65. GRB040422: optical observations at CrAO
  66. GRB 040423 (=H3175): A Long GRB Localized by HETE
  67. GRB040422, optical observations at Loiano
  68. GRB040422 : I-band follow-up observation at Lulin Observatory
  69. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  70. GRB040422, BVRcIc field calibration
  71. GRB 040422,optical observation
  72. GRB040422: optical and NIR observations at the VLT
  73. GRB 040422: a long GRB detected with INTEGRAL
  74. GRB 040403, deep optical observations
  75. MASTER: HETE Alert 3163, 3167 technical optical observation
  76. INTEGRAL-SPI/ACS GRB data: timing correction
  77. IBAS GRB alerts 1739, 1740, 1741
  78. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  79. GRB 040403: Optical Observations
  80. GRB 040403 Optical Observations
  81. GRB 040403: Optical observations
  82. GRB 040403: optical observations
  83. GRB 040403: Optical Observations
  84. GRB 040403: a long GRB detected with INTEGRAL
  85. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  86. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  87. IBAS GRB Alert 1694
  88. GRB040323: NIR Observations and Variable Object
  89. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  90. GRB 040323, a dark GRB ?
  91. short hard GRB 040322
  92. GRB 040323: a long GRB detected with INTEGRAL
  93. IBAS GRB alerts 1679, 1680, 1681
  94. GRB040223: Deep NIR NTT data re-analysis
  95. GRB 040223: XMM-Newton results
  96. GRB040223, improved XMM position
  97. IBAS Alert 1678: not a GRB
  98. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  99. GRB 031203, possible supernova
  100. MASTER: RXTE GRB040308 optical observation

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