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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"

41696 results found.

  1. GRB031111, optical observations
  2. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  3. GRB031203: Chandra Observations
  4. GRB040106, follow-up radio observations
  5. GRB040106: refined X-ray transient position
  6. Follow-up on IBAS GRB Alert 1379
  7. IBAS GRB alert 1379
  8. SN 2003dh/GRB030329 late-time optical spectroscopy
  9. GRB040106, Radio Observations
  10. GRB040106, likely optical afterglow
  11. GRB040106: Second Epoch Optical Observations
  12. GRB 031220: Optical observations of Chandra X-ray sources
  13. XMM-Newton Images of GRB 040106
  14. GRB040106: optical observations with REM+ROSS
  15. GRB031220: observation at Univercity of Miyazaki
  16. GRB 040106: Optical observations
  17. XMM-Newton observation of GRB040106
  18. GRB 040106 : peak flux
  19. GRB 040106 : a long GRB detected with INTEGRAL
  20. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  21. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  22. IPN triangulation of GRB031219 (large error box)
  23. GRB 031220: Subaru observation
  24. GRB 031220: Optical observation at Tokyo Tech
  25. GRB031220: ROTSE-IIIb Optical Limits
  26. GRB031220 : Optical Observation of Lulin Observatory
  27. GRB 031203 I-band monitoring
  28. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  29. GRB 2974 follow-up observations
  30. GRB031203, improved XMM position
  31. GRB 031203: Discovery of a dust echo
  32. GRB 031203: SMARTS optical monitoring
  33. GRB 021203: A Normal GRB viewed far off axis?
  34. GRB 031203: Variable Radio Source
  35. GRB 031203: Magellan spectrum of possible GRB host
  36. GRB 031203: Optical/IR Astrometry
  37. GRB031203 K prime photometry: correction to galaxy coordinates
  38. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  39. XMM-Newton Observation of GRB031203
  40. GRB 031203: Deep NIR NTT & VLT observations
  41. GRB031203: K' Photometry of the likely GRB host
  42. XMM-Newton Observation of GRB031203
  43. GRB 031203: Radio detection
  44. GRB 031203: Further reports on December 4 observations
  45. GRB 031203: IR NTTobservations do not confirm REM detection
  46. GRB031203 : Optical Observation of Lulin Observatory
  47. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  48. GRB 031203: Apparent Spectral Break
  49. GRB031203: Planned XMM-Newton observation II
  50. GRB 031203: IR REM Observations
  51. GRB031203: Optical Observations
  52. GRB 031203 XMM-Newton observation
  53. GRB 031203: Optical/IR SMARTS Observations
  54. GRB031203: Planned XMM-Newton observation
  55. IPN triangulation of GRB031127A and B (quasi-simultaneous; large error boxes)
  56. GRB 031203: further analysis of INTEGRAL data
  57. GRB 031203: A long GRB detected with INTEGRAL
  58. IPN triangulation of GRB031201 (large error box)
  59. IPN triangulation of GRB031130 (large error box)
  60. GRB031111A, prompt optical observations
  61. GRB 030329: Planned XMM-Newton Observation
  62. IPN triangulation of GRB031120 (two large error boxes)
  63. GRB 031111, Radio observations
  64. IPN triangulation of GRB031107 (two large error boxes)
  65. GRB 031111: Optical observations
  66. GRB 031111, optical observations
  67. SN 2003jd (SN/GRB?) -- X-ray Observations
  68. HETE Prompt GRB Spectral Analyses
  69. IPN triangulation of GRB031111 (=H2924): small error box
  70. XRF031109 (=H2919): A very long XRF localized by HETE
  71. IPN triangulation of GRB031108 (large error box)
  72. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  73. GRB030929/SN2003jd association unlikely based on IPN localiztion
  74. Lulin optical follow-up observations of GRB031026
  75. SN 2003jd (SN/GRB?), Radio Observations
  76. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  77. GRB 031026: Further Ic Observations
  78. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  79. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  80. IPN triangulation of GRB031024 (single error box)
  81. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  82. GRB 031026: Ic Observations
  83. GRB031026 : KISO optical follow-up observation
  84. GRB030329: radio observations at RT-22 (CrAO)
  85. IPN triangulation of GRB031016 (two large error boxes)
  86. HETE Prompt GRB Light Curves and Color-Color Diagrams
  87. Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
  88. XRF 030824: additional observations at CFHT
  89. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  90. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  91. XRF 030723: Subaru Optical Observations
  92. IPN triangulation of GRB031004B (annulus)
  93. A burst from SGR 1806-20 detected with IBAS
  94. XRF 030824: Early follow-up observation at Kiso observatory
  95. XRF 030723: Detection of the likely host galaxy
  96. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  97. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  98. IPN triangulation of GRB030922A (large error box)
  99. IPN triangulation of GRB030921 (large error box)
  100. GRB030913: Subaru Optical Observations

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