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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"
  1. GRB 040730: Optical observations
  2. GRB 040730: a long GRB detected with INTEGRAL
  3. Ongoing activity of SGR 1806-20
  4. GRB040624: optical monitoring at TNG
  5. XRF 040701 - optical observations of the decaying Chandra source
  6. XRF040701: Second-Epoch Chandra Observations
  7. Cancellation of IBAS/INTEGRAL GRB alerts
  8. XRF040701: VLA Observations
  9. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  10. XRF040701: First-Epoch Chandra Observations
  11. IBAS Alert 1836: NOT a real GRB
  12. GRB040709 J,H-band observations
  13. GRB040624, optical observations
  14. GRB040706:observation at University of Miyazaki
  15. XRF 040701, optical observations
  16. XRF040701 (=U11548): a bright XRF detected by HETE
  17. GRB 040624: optical observations
  18. Optical Observations of GRB040624
  19. GRB 040624: optical observations at TNG and VLT
  20. MASTER: GRB 040624 optical observation after 0,48d
  21. GRB 040624: R-band observations
  22. GRB 040624, optical observations
  23. GRB 040624 - A long GRB detected with INTEGRAL
  24. GRB 030329: Rebrightening of hyperluminal ejecta.
  25. IPN Summary of SGR1806-20 Activity in 2004
  26. GRB040511: Retraction of redshift identification
  27. SGR 1806-20: no IR variability of the proposed counterparts
  28. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  29. SGR 1806-20, potential NIR counterpart
  30. GRB 040606: Optical observations
  31. MASTER: HETE Alert 3274 optical observation
  32. Activivty of SGR 1806-20
  33. IPN triangulation of an intense intermediate burst from SGR1806-20
  34. GRB 040511, very fast decay?
  35. GRB 030324: Detection and Color of Host Galaxy
  36. GRB 040511: NIR observations with REM
  37. GRB040511: Redshift identifcation
  38. GRB 040511: Optical limit
  39. GRB040511: Candidate optical/NIR afterglow
  40. IBAS GRB Alerts n.1785 to 1791
  41. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  42. GRB 040511: Second Epoch Optical Observations
  43. IBAS GRB Alerts 1781-4
  44. GRB 040511: Optical observations
  45. GRB 040511: Optical Observations
  46. GRB040511: Optical Observations
  47. GRB040511: Optical Observations
  48. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  49. IBAS GRB Alert number 1774: NOT a real GRB
  50. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  51. IBAS Alerts 1771 and 1772: NOT a real GRB
  52. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  53. IPN triangulation of GRB040425 (=H3183)
  54. On Line Availability of Archival HETE Fregate Data and Lightcurves
  55. GRB040422: optical observations at Xinglong Observatory
  56. GRB040422: optical observations at CrAO
  57. GRB 040423 (=H3175): A Long GRB Localized by HETE
  58. GRB040422, optical observations at Loiano
  59. GRB040422 : I-band follow-up observation at Lulin Observatory
  60. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  61. GRB040422, BVRcIc field calibration
  62. GRB 040422,optical observation
  63. GRB040422: optical and NIR observations at the VLT
  64. GRB 040422: a long GRB detected with INTEGRAL
  65. GRB 040403, deep optical observations
  66. MASTER: HETE Alert 3163, 3167 technical optical observation
  67. INTEGRAL-SPI/ACS GRB data: timing correction
  68. IBAS GRB alerts 1739, 1740, 1741
  69. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  70. GRB 040403: Optical Observations
  71. GRB 040403 Optical Observations
  72. GRB 040403: Optical observations
  73. GRB 040403: optical observations
  74. GRB 040403: Optical Observations
  75. GRB 040403: a long GRB detected with INTEGRAL
  76. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  77. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  78. IBAS GRB Alert 1694
  79. GRB040323: NIR Observations and Variable Object
  80. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  81. GRB 040323, a dark GRB ?
  82. short hard GRB 040322
  83. GRB 040323: a long GRB detected with INTEGRAL
  84. IBAS GRB alerts 1679, 1680, 1681
  85. GRB040223: Deep NIR NTT data re-analysis
  86. GRB 040223: XMM-Newton results
  87. GRB040223, improved XMM position
  88. IBAS Alert 1678: not a GRB
  89. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  90. GRB 031203, possible supernova
  91. MASTER: RXTE GRB040308 optical observation
  92. IBAS results on a burst from SGR1806-20
  93. INTEGRAL detection of activity from SGR1806-20
  94. RXTE GRB040229 optical observation: no candidate
  95. GRB 040228 Optical observations
  96. IPN triangulation of GRB040228 (H3066, H3067)
  97. GRB040228 : KISO optical follow-up observation
  98. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  99. GRB 040223: Deep NIR NTT observations
  100. GRB 040223 : Optical observation (non-detection)

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