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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"
  1. GRBlog: Compilation of all GCN Circ. data
  2. IPN detection of renewed activity from SGR1806-20
  3. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  4. IPN triangulation of GRB030710 (annulus)
  5. IPN triangulation of GRB030709 (annulus)
  6. GRB030706 triangulation (single large error box)
  7. IPN triangulation of GRB030706 (annulus)
  8. IPN triangulation of GRB030629 (annulus)
  9. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  10. 030629 NOT a real GRB
  11. GRB030329, optical observation in May
  12. IPN triangulation of GRB030626 (single large error box)
  13. IPN triangulation of GRB030626 (two large error boxes)
  14. GRB030329: second XMM-Newton observation
  15. GRB030418: R optical observations
  16. HETE detection of burst from SGR1806-20
  17. GRB030329 -- RATAN-600 data in April-May
  18. Final IPN error ellipse for GRB021206 (the polarized GRB)
  19. GRB 021206, Radio afterglow candidate
  20. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  21. IPN triangulation of GRB030607 (annulus)
  22. IPN triangulation of GRB030606 (two alternate error boxes)
  23. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  24. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  25. IPN triangulation of GRB030605B (annulus)
  26. GRB 030528: Optical Observations
  27. IPN triangulation of GRB030605 (annulus)
  28. GRB 030528: tentative NIR counterpart
  29. GRB 030528, radio observations
  30. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  31. GRB030329, further radio observations at GMRT
  32. GRB030528, BVRI field photometry
  33. IPN triangulation of GRB030601 (annulus)
  34. GRB030329, SPM optical observations
  35. GRB030528: Chandra TOO Planned
  36. GRB 030519B: optical observations.
  37. MASTER: optical observation GRB030601
  38. GRB030528(=H2724): Revised SXC Localization
  39. GRB 030329: optical observations
  40. GRB 030329/SN 2003dh: Jitter Episode
  41. GRB 030528, Teramo optical observation
  42. GRB 030528 Bisei optical observation
  43. GRB030528 (H2724): A long GRB localized by HETE
  44. GRB 030329: Correction to GCN 2254
  45. GRB 030329: Optical Observations
  46. GRB 030528: Optical observations at RIKEN
  47. GRB 030528 (=H2724) Kyoto optical observation
  48. IPN triangulation of GRB030523B (annulus)
  49. GRB 030416: Optical Observations
  50. GRB 030329: Planned XMM-Newton Observation
  51. IPN triangulation of GRB030523 (annulus)
  52. GRB 030329: optical photometry at various french observatories
  53. GRB 030329: optical photometry at Belesta observatory (France)
  54. GRB030329, Optical observations
  55. GRB 030329/SN 2003dh: Possible increase in brightness
  56. GRB 030329: HST ACS Observations of the Host
  57. GRB 030329 Optical Observations
  58. GRB030329: XMM-Newton observation
  59. GRB 021004: HST observations
  60. GRB030324: Further Observations of the Candidate Optical Afterglow
  61. GRB030519B (=H2716): Peak Fluxes, Fluences, and Energy Spectrum
  62. IPN triangulation of GRB030519B=H2716 (small error box)
  63. GRB 030418: Second Epoch Optical Observations with Magellan
  64. GRB030519B (=H2716): A Long, Bright GRB Localized by the HETE WXM
  65. IPN triangulation of GRB030519 (annulus)
  66. IPN triangulation of GRB030518C (annulus)
  67. IPN triangulation of GRB030518B (annulus)
  68. IPN triangulation of GRB030518A (annulus)
  69. IPN triangulation of GRB030514 (annulus)
  70. HETE GRB030329, correction to Rc Observations in Loiano
  71. IPN triangulation of GRB030513 (annulus)
  72. IPN triangulation of GRB030509B (annulus)
  73. GRB 030329: Optical limit (contemporaneous imaging)
  74. GRB 030501: final TAROT limits
  75. IPN triangulation of GRB030509 (small errror box)
  76. IPN triangulation of GRB030509 - correction
  77. IPN triangulation of GRB030509 (single error box)
  78. GRB030329: RTT150 optical observations
  79. GRB030329, BVRI photometry
  80. GRB030429, refiend optical brightness
  81. GRB 030329: Optical limit (contemporaneous photography)
  82. GRB030418, BVRcIc field photometry
  83. GRB 030429: Redshift of neighbor galaxy
  84. GRB030429, BVRcIc field photometry
  85. GRB030429: RTT150 optical obs., correction to GCN 2208
  86. GRB 030329: High-Resolution Spectroscopy of the Host
  87. GRB030429 (=H2695): A Long GRB Localized by the HETE WXM and SXC
  88. GRB030418 (=H2686): A Long, X-Ray-Rich GRB Localized by the HETE WXM
  89. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  90. GRB030429: RTT150 optical observations, a possible host galaxy
  91. IPN triangulation of GRB030506 (annulus)
  92. IPN triangulation of GRB030505B (large error box)
  93. IPN triangulation of GRB030505A (annulus)
  94. GRB030329: RTT150 optical observations and upper limit for a host
  95. GRB 030329: all-sky CCD images by K. Shiokawa immediately after the burst
  96. GRB030501, optical observation
  97. GRB030501 observation report
  98. GRB030501C triangulation (annulus)
  99. GRB030501 triangulation (correction to GCN 2194)
  100. GRB030329: RTT150 optical observations and upper limit for a host

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