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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"

24889 results found.

  1. CXO observation of GRB 040812
  2. GRB 040812: radio observations
  3. GRB040812, optical/IR observations
  4. GRB 040812: a long GRB detected by INTEGRAL
  5. XRF040701: Optical Observations at ESO
  6. GRB 040730, infrared observations
  7. GRB 040730: a long GRB detected with INTEGRAL
  8. Ongoing activity of SGR 1806-20
  9. GRB040624: optical monitoring at TNG
  10. XRF 040701 - optical observations of the decaying Chandra source
  11. XRF040701: Second-Epoch Chandra Observations
  12. XRF040701: VLA Observations
  13. XRF040701: First-Epoch Chandra Observations
  14. GRB040624, optical observations
  15. GRB040706:observation at University of Miyazaki
  16. Optical Observations of GRB040624
  17. GRB 040624: optical observations at TNG and VLT
  18. MASTER: GRB 040624 optical observation after 0,48d
  19. GRB 040624, optical observations
  20. GRB 040624 - A long GRB detected with INTEGRAL
  21. GRB 030329: Rebrightening of hyperluminal ejecta.
  22. IPN Summary of SGR1806-20 Activity in 2004
  23. SGR 1806-20: no IR variability of the proposed counterparts
  24. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  25. SGR 1806-20, potential NIR counterpart
  26. GRB 040606: Optical observations
  27. MASTER: HETE Alert 3274 optical observation
  28. Activivty of SGR 1806-20
  29. GRB 040511, very fast decay?
  30. GRB 030324: Detection and Color of Host Galaxy
  31. GRB 040511: NIR observations with REM
  32. GRB040511: Candidate optical/NIR afterglow
  33. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  34. GRB 040511: Second Epoch Optical Observations
  35. GRB 040511: Optical observations
  36. GRB 040511: Optical Observations
  37. GRB040511: Optical Observations
  38. GRB040511: Optical Observations
  39. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  40. GRB 040423 (=H3175): A Long GRB Localized by HETE
  41. GRB040422 : I-band follow-up observation at Lulin Observatory
  42. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  43. GRB040422, BVRcIc field calibration
  44. GRB 040422,optical observation
  45. GRB 040422: a long GRB detected with INTEGRAL
  46. GRB 040403, deep optical observations
  47. MASTER: HETE Alert 3163, 3167 technical optical observation
  48. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  49. GRB 040403: Optical observations
  50. GRB 040403: a long GRB detected with INTEGRAL
  51. GRB040323: NIR Observations and Variable Object
  52. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  53. GRB 040323, a dark GRB ?
  54. GRB 040323: a long GRB detected with INTEGRAL
  55. GRB040223: Deep NIR NTT data re-analysis
  56. GRB 040223: XMM-Newton results
  57. GRB040223, improved XMM position
  58. GRB 031203, possible supernova
  59. MASTER: RXTE GRB040308 optical observation
  60. IBAS results on a burst from SGR1806-20
  61. INTEGRAL detection of activity from SGR1806-20
  62. RXTE GRB040229 optical observation: no candidate
  63. GRB 040228 Optical observations
  64. GRB040228 : KISO optical follow-up observation
  65. GRB 040223: Deep NIR NTT observations
  66. GRB 040223 : Optical observation (non-detection)
  67. XMM-Newton Images of GRB 040223
  68. GRB 040223, VLA observations
  69. GRB 040223: REM IJK Observations
  70. GRB 040223 XMM-Newton observation ...
  71. GRB 031203 XMM-Newton observation
  72. GRB 040223: further offline analysis
  73. GRB031111, optical observations
  74. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  75. GRB031203: Chandra Observations
  76. GRB040106: refined X-ray transient position
  77. SN 2003dh/GRB030329 late-time optical spectroscopy
  78. GRB 031220: Optical observations of Chandra X-ray sources
  79. XMM-Newton Images of GRB 040106
  80. GRB031220: observation at Univercity of Miyazaki
  81. XMM-Newton observation of GRB040106
  82. GRB 040106 : peak flux
  83. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  84. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  85. GRB031220: Palomar Observations
  86. GRB 031220 : Kyoto Optical Observation
  87. GRB 031220: Subaru observation
  88. GRB 031220: Optical observation at Tokyo Tech
  89. GRB 2974 follow-up observations
  90. GRB031203, improved XMM position
  91. GRB 021203: A Normal GRB viewed far off axis?
  92. XMM-Newton Observations of GRB031203: Preliminary Images
  93. GRB 031203: Variable Radio Source
  94. GRB 031203: Magellan spectrum of possible GRB host
  95. GRB 031203: Optical/IR Astrometry
  96. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  97. XMM-Newton Observation of GRB031203
  98. GRB031203: K' Photometry of the likely GRB host
  99. XMM-Newton Observation of GRB031203
  100. GRB 031203: IR NTTobservations do not confirm REM detection

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