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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 GRB030607 (annulus)
  2. IPN triangulation of GRB030606 (two alternate error boxes)
  3. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  4. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  5. IPN triangulation of GRB030605B (annulus)
  6. GRB 030528: Optical Observations
  7. IPN triangulation of GRB030605 (annulus)
  8. GRB 030528: tentative NIR counterpart
  9. GRB 030528, radio observations
  10. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  11. GRB030329, further radio observations at GMRT
  12. GRB030528, BVRI field photometry
  13. IPN triangulation of GRB030601 (annulus)
  14. GRB030329, SPM optical observations
  15. GRB030528: Chandra TOO Planned
  16. GRB 030519B: optical observations.
  17. MASTER: optical observation GRB030601
  18. GRB030528(=H2724): Revised SXC Localization
  19. GRB 030329: optical observations
  20. GRB 030329/SN 2003dh: Jitter Episode
  21. GRB 030528, Teramo optical observation
  22. GRB 030528 Bisei optical observation
  23. GRB030528 (H2724): A long GRB localized by HETE
  24. GRB 030329: Correction to GCN 2254
  25. GRB 030329: Optical Observations
  26. GRB 030528: Optical observations at RIKEN
  27. GRB 030528 (=H2724) Kyoto optical observation
  28. IPN triangulation of GRB030523B (annulus)
  29. GRB 030416: Optical Observations
  30. GRB 030329: Planned XMM-Newton Observation
  31. IPN triangulation of GRB030523 (annulus)
  32. GRB 030329: optical photometry at various french observatories
  33. GRB 030329: optical photometry at Belesta observatory (France)
  34. GRB030329, Optical observations
  35. GRB 030329/SN 2003dh: Possible increase in brightness
  36. GRB 030329: HST ACS Observations of the Host
  37. GRB 030329 Optical Observations
  38. GRB030329: XMM-Newton observation
  39. GRB 021004: HST observations
  40. GRB030324: Further Observations of the Candidate Optical Afterglow
  41. GRB030519B (=H2716): Peak Fluxes, Fluences, and Energy Spectrum
  42. IPN triangulation of GRB030519B=H2716 (small error box)
  43. GRB 030418: Second Epoch Optical Observations with Magellan
  44. GRB030519B (=H2716): A Long, Bright GRB Localized by the HETE WXM
  45. IPN triangulation of GRB030519 (annulus)
  46. IPN triangulation of GRB030518C (annulus)
  47. IPN triangulation of GRB030518B (annulus)
  48. IPN triangulation of GRB030518A (annulus)
  49. IPN triangulation of GRB030514 (annulus)
  50. HETE GRB030329, correction to Rc Observations in Loiano
  51. IPN triangulation of GRB030513 (annulus)
  52. IPN triangulation of GRB030509B (annulus)
  53. GRB 030329: Optical limit (contemporaneous imaging)
  54. GRB 030501: final TAROT limits
  55. IPN triangulation of GRB030509 (small errror box)
  56. IPN triangulation of GRB030509 - correction
  57. IPN triangulation of GRB030509 (single error box)
  58. GRB030329: RTT150 optical observations
  59. GRB030329, BVRI photometry
  60. GRB030429, refiend optical brightness
  61. GRB 030329: Optical limit (contemporaneous photography)
  62. GRB030418, BVRcIc field photometry
  63. GRB 030429: Redshift of neighbor galaxy
  64. GRB030429, BVRcIc field photometry
  65. GRB030429: RTT150 optical obs., correction to GCN 2208
  66. GRB 030329: High-Resolution Spectroscopy of the Host
  67. GRB030429 (=H2695): A Long GRB Localized by the HETE WXM and SXC
  68. GRB030418 (=H2686): A Long, X-Ray-Rich GRB Localized by the HETE WXM
  69. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  70. GRB030429: RTT150 optical observations, a possible host galaxy
  71. IPN triangulation of GRB030506 (annulus)
  72. IPN triangulation of GRB030505B (large error box)
  73. IPN triangulation of GRB030505A (annulus)
  74. GRB030329: RTT150 optical observations and upper limit for a host
  75. GRB 030329: all-sky CCD images by K. Shiokawa immediately after the burst
  76. GRB030501, optical observation
  77. GRB030501 observation report
  78. GRB030501C triangulation (annulus)
  79. GRB030501 triangulation (correction to GCN 2194)
  80. GRB030329: RTT150 optical observations and upper limit for a host
  81. GRB 030429: Radio Observations
  82. GRB 030429: redshift from VLT spectroscopy
  83. GRB 030429: IR photometry with IRSF/SIRIUS
  84. GRB030501B triangulation (single error box)
  85. GRB 030329 Optical Observations
  86. GRB030328, optical observation
  87. GRB 030329, BVRI photometry
  88. GRB030429: Optical Observations
  89. GRB030501: TAROT candidate afterglow present in archival images
  90. GRB 030501: TAROT possible candidate counterpart
  91. IPN triangulation of GRB030501 (IBIS event; annulus)
  92. IPN triangulation of GRB030501B (annulus)
  93. GRB 030429: confirmation of afterglow candidate
  94. GRB030429, possible optical counterpart
  95. GRB030501 localized by INTEGRAL
  96. GRB030425: CrAO optical observation
  97. IPN triangulation of GRB030429 (annulus)
  98. IPN triangulation of GRB030428 (two large error boxes)
  99. GRB 030329 Oprical observations in Rozhen observatory
  100. GRB 030429: ROTSE-III observations

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