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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"

15985 results found.

  1. GRB 040511: Optical Observations
  2. GRB040511: Optical Observations
  3. GRB040511: Optical Observations
  4. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  5. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  6. On Line Availability of Archival HETE Fregate Data and Lightcurves
  7. GRB040422: optical observations at Xinglong Observatory
  8. GRB040422: optical observations at CrAO
  9. GRB 040423 (=H3175): A Long GRB Localized by HETE
  10. GRB040422, optical observations at Loiano
  11. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  12. GRB 040422,optical observation
  13. GRB040422: optical and NIR observations at the VLT
  14. GRB 040403, deep optical observations
  15. MASTER: HETE Alert 3163, 3167 technical optical observation
  16. GRB 040403: Optical Observations
  17. GRB 040403 Optical Observations
  18. GRB 040403: Optical observations
  19. GRB 040403: optical observations
  20. GRB 040403: Optical Observations
  21. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  22. GRB 040323, a dark GRB ?
  23. GRB040223, improved XMM position
  24. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  25. MASTER: RXTE GRB040308 optical observation
  26. RXTE GRB040229 optical observation: no candidate
  27. GRB 040228 Optical observations
  28. GRB040228 : KISO optical follow-up observation
  29. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  30. GRB 040223 : Optical observation (non-detection)
  31. GRB031111, optical observations
  32. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  33. GRB040106: refined X-ray transient position
  34. SN 2003dh/GRB030329 late-time optical spectroscopy
  35. GRB040106, Radio Observations
  36. GRB040106, likely optical afterglow
  37. GRB040106: Second Epoch Optical Observations
  38. GRB 031220: Optical observations of Chandra X-ray sources
  39. GRB040106: optical observations with REM+ROSS
  40. GRB 040106: Optical observations
  41. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  42. GRB 031220 : Kyoto Optical Observation
  43. GRB 031220: Optical observation at Tokyo Tech
  44. GRB031220: ROTSE-IIIb Optical Limits
  45. GRB031220 : Optical Observation of Lulin Observatory
  46. GRB 031203: Discovery of a dust echo
  47. GRB 031203: SMARTS optical monitoring
  48. GRB 031203: Optical/IR Astrometry
  49. IPN/HETE localization of GRB031203B (=H2949; large error box)
  50. GRB031203 : Optical Observation of Lulin Observatory
  51. GRB031203: Optical Observations
  52. GRB 031203: Optical/IR SMARTS Observations
  53. GRB031111A, prompt optical observations
  54. GRB 031111B (= H2925) : Kyoto Optical Observation
  55. GRB 031111: Optical observations
  56. GRB 031111, optical observations
  57. SN 2003jd (SN/GRB?) -- X-ray Observations
  58. XRF031109 (=H2919): A very long XRF localized by HETE
  59. Lulin optical follow-up observations of GRB031026
  60. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  61. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  62. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  63. GRB031026 : KISO optical follow-up observation
  64. GRB030329: radio observations at RT-22 (CrAO)
  65. XRF 030723: Subaru Optical Observations
  66. XRF 030723: Detection of the likely host galaxy
  67. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  68. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  69. GRB030913: Subaru Optical Observations
  70. GRB 030913: ROTSE-3c Optical Observations
  71. GRB030913, candidate afterglow observations
  72. GRB 030913, optical candidate
  73. GRB030913: AAVSO optical observations
  74. GRB030913 (=H2849): Confirmation of the Flight Localization
  75. Magellan Observations of GRB030725 (=H2779)
  76. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  77. GRB 030913: Optical limit at RIKEN
  78. XRF030824: Optical observations
  79. XRF030824: Second-epoch Palomar observations
  80. XRF030824: optical observations
  81. GRB030823: optical observations
  82. GRB030823: Palomar observations
  83. GRB030823: optical observation at Tokyo Tech
  84. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  85. GRB 030817 = H2808 TAROT optical observations
  86. SGR 1808-20 (=H2802): A Possible new SGR
  87. GRB 021206 Optical Observations
  88. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  89. XRF 030723: Detection of a rebrightening in the optical afterglow
  90. GRB030725: Optical observations
  91. XRF030723, BVRcIc field photometry update
  92. GRB021206 optical counterpart upper limit
  93. IPN triangulation of GRB030725 (=H2779; small error box)
  94. XRF030723 (=H2777): Second Epoch Magellan Observations
  95. GRB 030725: optical observations.
  96. GRB030725, optical transient observations
  97. XRF030723 Radio Observations
  98. XRF 030723: confirmation of fading optical counterpart
  99. XRF030723(=H2777): Chandra Observations
  100. Magellan Observations of XRF030723 (=H2777)

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