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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. GRB 030519B: optical observations.
  2. MASTER: optical observation GRB030601
  3. GRB030528(=H2724): Revised SXC Localization
  4. GRB 030329: optical observations
  5. GRB 030329/SN 2003dh: Jitter Episode
  6. GRB 030528, Teramo optical observation
  7. GRB 030528 Bisei optical observation
  8. GRB030528 (H2724): A long GRB localized by HETE
  9. GRB 030329: Correction to GCN 2254
  10. GRB 030329: Optical Observations
  11. GRB 030528: Optical observations at RIKEN
  12. GRB 030528 (=H2724) Kyoto optical observation
  13. IPN triangulation of GRB030523B (annulus)
  14. GRB 030416: Optical Observations
  15. GRB 030329: Planned XMM-Newton Observation
  16. IPN triangulation of GRB030523 (annulus)
  17. GRB 030329: optical photometry at various french observatories
  18. GRB 030329: optical photometry at Belesta observatory (France)
  19. GRB030329, Optical observations
  20. GRB 030329/SN 2003dh: Possible increase in brightness
  21. GRB 030329: HST ACS Observations of the Host
  22. GRB 030329 Optical Observations
  23. GRB030329: XMM-Newton observation
  24. GRB 021004: HST observations
  25. GRB030324: Further Observations of the Candidate Optical Afterglow
  26. GRB030519B (=H2716): Peak Fluxes, Fluences, and Energy Spectrum
  27. IPN triangulation of GRB030519B=H2716 (small error box)
  28. GRB 030418: Second Epoch Optical Observations with Magellan
  29. GRB030519B (=H2716): A Long, Bright GRB Localized by the HETE WXM
  30. IPN triangulation of GRB030519 (annulus)
  31. IPN triangulation of GRB030518C (annulus)
  32. IPN triangulation of GRB030518B (annulus)
  33. IPN triangulation of GRB030518A (annulus)
  34. IPN triangulation of GRB030514 (annulus)
  35. HETE GRB030329, correction to Rc Observations in Loiano
  36. IPN triangulation of GRB030513 (annulus)
  37. IPN triangulation of GRB030509B (annulus)
  38. GRB 030329: Optical limit (contemporaneous imaging)
  39. GRB 030501: final TAROT limits
  40. IPN triangulation of GRB030509 (small errror box)
  41. IPN triangulation of GRB030509 - correction
  42. IPN triangulation of GRB030509 (single error box)
  43. GRB030329: RTT150 optical observations
  44. GRB030329, BVRI photometry
  45. GRB030429, refiend optical brightness
  46. GRB 030329: Optical limit (contemporaneous photography)
  47. GRB030418, BVRcIc field photometry
  48. GRB 030429: Redshift of neighbor galaxy
  49. GRB030429, BVRcIc field photometry
  50. GRB030429: RTT150 optical obs., correction to GCN 2208
  51. GRB 030329: High-Resolution Spectroscopy of the Host
  52. GRB030429 (=H2695): A Long GRB Localized by the HETE WXM and SXC
  53. GRB030418 (=H2686): A Long, X-Ray-Rich GRB Localized by the HETE WXM
  54. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  55. GRB030429: RTT150 optical observations, a possible host galaxy
  56. IPN triangulation of GRB030506 (annulus)
  57. IPN triangulation of GRB030505B (large error box)
  58. IPN triangulation of GRB030505A (annulus)
  59. GRB030329: RTT150 optical observations and upper limit for a host
  60. GRB 030329: all-sky CCD images by K. Shiokawa immediately after the burst
  61. GRB030501, optical observation
  62. GRB030501 observation report
  63. GRB030501C triangulation (annulus)
  64. GRB030501 triangulation (correction to GCN 2194)
  65. GRB030329: RTT150 optical observations and upper limit for a host
  66. GRB 030429: Radio Observations
  67. GRB 030429: redshift from VLT spectroscopy
  68. GRB 030429: IR photometry with IRSF/SIRIUS
  69. GRB030501B triangulation (single error box)
  70. GRB 030329 Optical Observations
  71. GRB030328, optical observation
  72. GRB 030329, BVRI photometry
  73. GRB030429: Optical Observations
  74. GRB030501: TAROT candidate afterglow present in archival images
  75. GRB 030501: TAROT possible candidate counterpart
  76. IPN triangulation of GRB030501 (IBIS event; annulus)
  77. IPN triangulation of GRB030501B (annulus)
  78. GRB 030429: confirmation of afterglow candidate
  79. GRB030429, possible optical counterpart
  80. GRB030501 localized by INTEGRAL
  81. GRB030425: CrAO optical observation
  82. IPN triangulation of GRB030429 (annulus)
  83. IPN triangulation of GRB030428 (two large error boxes)
  84. GRB 030329 Oprical observations in Rozhen observatory
  85. GRB 030429: ROTSE-III observations
  86. GRB 030324: Radio Observations
  87. GRB030329 observed as a sudden ionospheric disturbance (SID)
  88. IPN triangulation of GRB030426 (annulus)
  89. SNeIa AS THE POSSIBLE PROGENITORS OF SHORT-DURATION GRBs.
  90. IPN triangulation of GRB030425 (single error box)
  91. GRB030329, SPM optical observations (Correction)
  92. GRB030329, SPM optical observations
  93. GRB 030329, the review of the sky area in plate archive (1950-1998)
  94. GRB 030329: Spectral Evolution of SN 2003dh
  95. Optical Observations of GRB 030418 with Magellan
  96. GRB 030329: optical spectropolarimetry at VLT
  97. IPN triangulation of GRB030422C (annulus)
  98. IPN triangulation of GRB030422B (annulus)
  99. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  100. GRB030329: optical polarization

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