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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').
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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"

24980 results found.

  1. XRF 040701 - optical observations of the decaying Chandra source
  2. XRF040701: Second-Epoch Chandra Observations
  3. XRF040701: VLA Observations
  4. XRF040701: First-Epoch Chandra Observations
  5. GRB040624, optical observations
  6. GRB040706:observation at University of Miyazaki
  7. Optical Observations of GRB040624
  8. GRB 040624: optical observations at TNG and VLT
  9. MASTER: GRB 040624 optical observation after 0,48d
  10. GRB 040624, optical observations
  11. GRB 040624 - A long GRB detected with INTEGRAL
  12. GRB 030329: Rebrightening of hyperluminal ejecta.
  13. IPN Summary of SGR1806-20 Activity in 2004
  14. SGR 1806-20: no IR variability of the proposed counterparts
  15. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  16. SGR 1806-20, potential NIR counterpart
  17. GRB 040606: Optical observations
  18. MASTER: HETE Alert 3274 optical observation
  19. Activivty of SGR 1806-20
  20. GRB 040511, very fast decay?
  21. GRB 030324: Detection and Color of Host Galaxy
  22. GRB 040511: NIR observations with REM
  23. GRB040511: Candidate optical/NIR afterglow
  24. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  25. GRB 040511: Second Epoch Optical Observations
  26. GRB 040511: Optical observations
  27. GRB 040511: Optical Observations
  28. GRB040511: Optical Observations
  29. GRB040511: Optical Observations
  30. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  31. GRB 040423 (=H3175): A Long GRB Localized by HETE
  32. GRB040422 : I-band follow-up observation at Lulin Observatory
  33. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  34. GRB040422, BVRcIc field calibration
  35. GRB 040422,optical observation
  36. GRB 040422: a long GRB detected with INTEGRAL
  37. GRB 040403, deep optical observations
  38. MASTER: HETE Alert 3163, 3167 technical optical observation
  39. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  40. GRB 040403: Optical observations
  41. GRB 040403: a long GRB detected with INTEGRAL
  42. GRB040323: NIR Observations and Variable Object
  43. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  44. GRB 040323, a dark GRB ?
  45. GRB 040323: a long GRB detected with INTEGRAL
  46. GRB040223: Deep NIR NTT data re-analysis
  47. GRB 040223: XMM-Newton results
  48. GRB040223, improved XMM position
  49. GRB 031203, possible supernova
  50. MASTER: RXTE GRB040308 optical observation
  51. IBAS results on a burst from SGR1806-20
  52. INTEGRAL detection of activity from SGR1806-20
  53. RXTE GRB040229 optical observation: no candidate
  54. GRB 040228 Optical observations
  55. GRB040228 : KISO optical follow-up observation
  56. GRB 040223: Deep NIR NTT observations
  57. GRB 040223 : Optical observation (non-detection)
  58. XMM-Newton Images of GRB 040223
  59. GRB 040223, VLA observations
  60. GRB 040223: REM IJK Observations
  61. GRB 040223 XMM-Newton observation ...
  62. GRB 031203 XMM-Newton observation
  63. GRB 040223: further offline analysis
  64. GRB031111, optical observations
  65. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  66. GRB031203: Chandra Observations
  67. GRB040106: refined X-ray transient position
  68. SN 2003dh/GRB030329 late-time optical spectroscopy
  69. GRB 031220: Optical observations of Chandra X-ray sources
  70. XMM-Newton Images of GRB 040106
  71. GRB031220: observation at Univercity of Miyazaki
  72. XMM-Newton observation of GRB040106
  73. GRB 040106 : peak flux
  74. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  75. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  76. GRB031220: Palomar Observations
  77. GRB 031220 : Kyoto Optical Observation
  78. GRB 031220: Subaru observation
  79. GRB 031220: Optical observation at Tokyo Tech
  80. GRB 2974 follow-up observations
  81. GRB031203, improved XMM position
  82. GRB 021203: A Normal GRB viewed far off axis?
  83. XMM-Newton Observations of GRB031203: Preliminary Images
  84. GRB 031203: Variable Radio Source
  85. GRB 031203: Magellan spectrum of possible GRB host
  86. GRB 031203: Optical/IR Astrometry
  87. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  88. XMM-Newton Observation of GRB031203
  89. GRB031203: K' Photometry of the likely GRB host
  90. XMM-Newton Observation of GRB031203
  91. GRB 031203: IR NTTobservations do not confirm REM detection
  92. GRB031203 : Optical Observation of Lulin Observatory
  93. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  94. GRB 031203: Apparent Spectral Break
  95. GRB031203: Planned XMM-Newton observation II
  96. GRB 031203: IR REM Observations
  97. GRB031203: Optical Observations
  98. GRB 031203 XMM-Newton observation
  99. GRB031203: Planned XMM-Newton observation
  100. GRB 031203: further analysis of INTEGRAL data

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