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

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