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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"

41699 results found.

  1. GRB 031203 XMM-Newton observation
  2. GRB 040223: further offline analysis
  3. GRB 040223: a long GRB detected with INTEGRAL
  4. GRB031111, optical observations
  5. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  6. GRB031203: Chandra Observations
  7. GRB040106, follow-up radio observations
  8. GRB040106: refined X-ray transient position
  9. Follow-up on IBAS GRB Alert 1379
  10. IBAS GRB alert 1379
  11. SN 2003dh/GRB030329 late-time optical spectroscopy
  12. GRB040106, Radio Observations
  13. GRB040106, likely optical afterglow
  14. GRB040106: Second Epoch Optical Observations
  15. GRB 031220: Optical observations of Chandra X-ray sources
  16. XMM-Newton Images of GRB 040106
  17. GRB040106: optical observations with REM+ROSS
  18. GRB031220: observation at Univercity of Miyazaki
  19. GRB 040106: Optical observations
  20. XMM-Newton observation of GRB040106
  21. GRB 040106 : peak flux
  22. GRB 040106 : a long GRB detected with INTEGRAL
  23. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  24. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  25. IPN triangulation of GRB031219 (large error box)
  26. GRB 031220: Subaru observation
  27. GRB 031220: Optical observation at Tokyo Tech
  28. GRB031220: ROTSE-IIIb Optical Limits
  29. GRB031220 : Optical Observation of Lulin Observatory
  30. GRB 031203 I-band monitoring
  31. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  32. GRB 2974 follow-up observations
  33. GRB031203, improved XMM position
  34. GRB 031203: Discovery of a dust echo
  35. GRB 031203: SMARTS optical monitoring
  36. GRB 021203: A Normal GRB viewed far off axis?
  37. GRB 031203: Variable Radio Source
  38. GRB 031203: Magellan spectrum of possible GRB host
  39. GRB 031203: Optical/IR Astrometry
  40. GRB031203 K prime photometry: correction to galaxy coordinates
  41. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  42. XMM-Newton Observation of GRB031203
  43. GRB 031203: Deep NIR NTT & VLT observations
  44. GRB031203: K' Photometry of the likely GRB host
  45. XMM-Newton Observation of GRB031203
  46. GRB 031203: Radio detection
  47. GRB 031203: Further reports on December 4 observations
  48. GRB 031203: IR NTTobservations do not confirm REM detection
  49. GRB031203 : Optical Observation of Lulin Observatory
  50. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  51. GRB 031203: Apparent Spectral Break
  52. GRB031203: Planned XMM-Newton observation II
  53. GRB 031203: IR REM Observations
  54. GRB031203: Optical Observations
  55. GRB 031203 XMM-Newton observation
  56. GRB 031203: Optical/IR SMARTS Observations
  57. GRB031203: Planned XMM-Newton observation
  58. IPN triangulation of GRB031127A and B (quasi-simultaneous; large error boxes)
  59. GRB 031203: further analysis of INTEGRAL data
  60. GRB 031203: A long GRB detected with INTEGRAL
  61. IPN triangulation of GRB031201 (large error box)
  62. IPN triangulation of GRB031130 (large error box)
  63. GRB031111A, prompt optical observations
  64. GRB 030329: Planned XMM-Newton Observation
  65. IPN triangulation of GRB031120 (two large error boxes)
  66. GRB 031111, Radio observations
  67. IPN triangulation of GRB031107 (two large error boxes)
  68. GRB 031111: Optical observations
  69. GRB 031111, optical observations
  70. SN 2003jd (SN/GRB?) -- X-ray Observations
  71. HETE Prompt GRB Spectral Analyses
  72. IPN triangulation of GRB031111 (=H2924): small error box
  73. XRF031109 (=H2919): A very long XRF localized by HETE
  74. IPN triangulation of GRB031108 (large error box)
  75. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  76. GRB030929/SN2003jd association unlikely based on IPN localiztion
  77. Lulin optical follow-up observations of GRB031026
  78. SN 2003jd (SN/GRB?), Radio Observations
  79. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  80. GRB 031026: Further Ic Observations
  81. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  82. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  83. IPN triangulation of GRB031024 (single error box)
  84. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  85. GRB 031026: Ic Observations
  86. GRB031026 : KISO optical follow-up observation
  87. GRB030329: radio observations at RT-22 (CrAO)
  88. IPN triangulation of GRB031016 (two large error boxes)
  89. HETE Prompt GRB Light Curves and Color-Color Diagrams
  90. Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
  91. XRF 030824: additional observations at CFHT
  92. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  93. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  94. XRF 030723: Subaru Optical Observations
  95. IPN triangulation of GRB031004B (annulus)
  96. A burst from SGR 1806-20 detected with IBAS
  97. XRF 030824: Early follow-up observation at Kiso observatory
  98. XRF 030723: Detection of the likely host galaxy
  99. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  100. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC

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