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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"

41700 results found.

  1. GRB 040223 XMM-Newton observation ...
  2. GRB 031203 XMM-Newton observation
  3. GRB 040223: further offline analysis
  4. GRB 040223: a long GRB detected with INTEGRAL
  5. GRB031111, optical observations
  6. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  7. GRB031203: Chandra Observations
  8. GRB040106, follow-up radio observations
  9. GRB040106: refined X-ray transient position
  10. Follow-up on IBAS GRB Alert 1379
  11. IBAS GRB alert 1379
  12. SN 2003dh/GRB030329 late-time optical spectroscopy
  13. GRB040106, Radio Observations
  14. GRB040106, likely optical afterglow
  15. GRB040106: Second Epoch Optical Observations
  16. GRB 031220: Optical observations of Chandra X-ray sources
  17. XMM-Newton Images of GRB 040106
  18. GRB040106: optical observations with REM+ROSS
  19. GRB031220: observation at Univercity of Miyazaki
  20. GRB 040106: Optical observations
  21. XMM-Newton observation of GRB040106
  22. GRB 040106 : peak flux
  23. GRB 040106 : a long GRB detected with INTEGRAL
  24. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  25. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  26. IPN triangulation of GRB031219 (large error box)
  27. GRB 031220: Subaru observation
  28. GRB 031220: Optical observation at Tokyo Tech
  29. GRB031220: ROTSE-IIIb Optical Limits
  30. GRB031220 : Optical Observation of Lulin Observatory
  31. GRB 031203 I-band monitoring
  32. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  33. GRB 2974 follow-up observations
  34. GRB031203, improved XMM position
  35. GRB 031203: Discovery of a dust echo
  36. GRB 031203: SMARTS optical monitoring
  37. GRB 021203: A Normal GRB viewed far off axis?
  38. GRB 031203: Variable Radio Source
  39. GRB 031203: Magellan spectrum of possible GRB host
  40. GRB 031203: Optical/IR Astrometry
  41. GRB031203 K prime photometry: correction to galaxy coordinates
  42. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  43. XMM-Newton Observation of GRB031203
  44. GRB 031203: Deep NIR NTT & VLT observations
  45. GRB031203: K' Photometry of the likely GRB host
  46. XMM-Newton Observation of GRB031203
  47. GRB 031203: Radio detection
  48. GRB 031203: Further reports on December 4 observations
  49. GRB 031203: IR NTTobservations do not confirm REM detection
  50. GRB031203 : Optical Observation of Lulin Observatory
  51. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  52. GRB 031203: Apparent Spectral Break
  53. GRB031203: Planned XMM-Newton observation II
  54. GRB 031203: IR REM Observations
  55. GRB031203: Optical Observations
  56. GRB 031203 XMM-Newton observation
  57. GRB 031203: Optical/IR SMARTS Observations
  58. GRB031203: Planned XMM-Newton observation
  59. IPN triangulation of GRB031127A and B (quasi-simultaneous; large error boxes)
  60. GRB 031203: further analysis of INTEGRAL data
  61. GRB 031203: A long GRB detected with INTEGRAL
  62. IPN triangulation of GRB031201 (large error box)
  63. IPN triangulation of GRB031130 (large error box)
  64. GRB031111A, prompt optical observations
  65. GRB 030329: Planned XMM-Newton Observation
  66. IPN triangulation of GRB031120 (two large error boxes)
  67. GRB 031111, Radio observations
  68. IPN triangulation of GRB031107 (two large error boxes)
  69. GRB 031111: Optical observations
  70. GRB 031111, optical observations
  71. SN 2003jd (SN/GRB?) -- X-ray Observations
  72. HETE Prompt GRB Spectral Analyses
  73. IPN triangulation of GRB031111 (=H2924): small error box
  74. XRF031109 (=H2919): A very long XRF localized by HETE
  75. IPN triangulation of GRB031108 (large error box)
  76. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  77. GRB030929/SN2003jd association unlikely based on IPN localiztion
  78. Lulin optical follow-up observations of GRB031026
  79. SN 2003jd (SN/GRB?), Radio Observations
  80. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  81. GRB 031026: Further Ic Observations
  82. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  83. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  84. IPN triangulation of GRB031024 (single error box)
  85. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  86. GRB 031026: Ic Observations
  87. GRB031026 : KISO optical follow-up observation
  88. GRB030329: radio observations at RT-22 (CrAO)
  89. IPN triangulation of GRB031016 (two large error boxes)
  90. HETE Prompt GRB Light Curves and Color-Color Diagrams
  91. Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
  92. XRF 030824: additional observations at CFHT
  93. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  94. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  95. XRF 030723: Subaru Optical Observations
  96. IPN triangulation of GRB031004B (annulus)
  97. A burst from SGR 1806-20 detected with IBAS
  98. XRF 030824: Early follow-up observation at Kiso observatory
  99. XRF 030723: Detection of the likely host galaxy
  100. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM

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