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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"

32494 results found.

  1. GRB 040223, VLA observations
  2. GRB 040223: REM IJK Observations
  3. GRB 040223 XMM-Newton observation ...
  4. GRB 031203 XMM-Newton observation
  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. 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. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  22. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  23. GRB 031203 I-band monitoring
  24. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  25. GRB 2974 follow-up observations
  26. GRB031203, improved XMM position
  27. GRB 031203: SMARTS optical monitoring
  28. GRB 021203: A Normal GRB viewed far off axis?
  29. GRB 031203: Variable Radio Source
  30. GRB 031203: Magellan spectrum of possible GRB host
  31. GRB 031203: Optical/IR Astrometry
  32. GRB031203 K prime photometry: correction to galaxy coordinates
  33. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  34. XMM-Newton Observation of GRB031203
  35. GRB031203: K' Photometry of the likely GRB host
  36. XMM-Newton Observation of GRB031203
  37. GRB 031203: Radio detection
  38. GRB 031203: Further reports on December 4 observations
  39. GRB 031203: IR NTTobservations do not confirm REM detection
  40. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  41. GRB 031203: Apparent Spectral Break
  42. GRB031203: Planned XMM-Newton observation II
  43. GRB 031203: IR REM Observations
  44. GRB031203: Optical Observations
  45. GRB 031203 XMM-Newton observation
  46. GRB 031203: Optical/IR SMARTS Observations
  47. GRB031203: Planned XMM-Newton observation
  48. GRB031111A, prompt optical observations
  49. GRB 031111, Radio observations
  50. GRB 031111: Optical observations
  51. GRB 031111, optical observations
  52. SN 2003jd (SN/GRB?) -- X-ray Observations
  53. IPN triangulation of GRB031111 (=H2924): small error box
  54. XRF031109 (=H2919): A very long XRF localized by HETE
  55. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  56. GRB030929/SN2003jd association unlikely based on IPN localiztion
  57. Lulin optical follow-up observations of GRB031026
  58. SN 2003jd (SN/GRB?), Radio Observations
  59. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  60. GRB 031026: Further Ic Observations
  61. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  62. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  63. IPN triangulation of GRB031024 (single error box)
  64. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  65. XRF 030824: additional observations at CFHT
  66. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  67. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  68. XRF 030723: Subaru Optical Observations
  69. XRF 030824: Early follow-up observation at Kiso observatory
  70. XRF 030723: Detection of the likely host galaxy
  71. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  72. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  73. IPN triangulation of GRB030922A (large error box)
  74. IPN triangulation of GRB030921 (large error box)
  75. GRB030913: Subaru Optical Observations
  76. GRB 030913: ROTSE-3c Optical Observations
  77. GRB030913: OT's limit by MASTER
  78. GRB030913, candidate afterglow observations
  79. GRB030913: AAVSO optical observations
  80. GRB030913 (=H2849): Confirmation of the Flight Localization
  81. GRB030913 (=H2849): TAROT Observations
  82. Magellan Observations of GRB030725 (=H2779)
  83. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  84. IBAS detection of bursts from SGR 1806-20
  85. Radio Observations of SGR1806-20
  86. GRB 030824: Candidate Follow-Up
  87. XRF030824: Second-epoch Palomar observations
  88. XRF030824: optical observations
  89. XRF030824: Palomar observations
  90. GRB030823: optical observation at Tokyo Tech
  91. RAPTOR observations of GRB030823
  92. IPN triangulation of GRB030821 (=H2814; refined error box)
  93. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  94. Summary of recent IPN and HETE detections of SGR bursts
  95. Clarification of GCN 2354 on SGR1806-20
  96. IPN detection of continued activity from SGR1806-20
  97. 030813 SGR event (Konus-Wind observation)
  98. SGR 1808-20 (=H2802): A Possible new SGR
  99. GRB 021206 Optical Observations
  100. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed

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