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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').
  1. XRF030723, optical observations
  2. XRF 030723, optical observations
  3. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  4. GRB030723, optical observations
  5. Konus-Wind detection of the bursts from SGR1806-20 region
  6. IBAS GRB Alerts 969 970
  7. SGR 1806-20, submm observations
  8. H2768, H2770, and H2771: Three Bursts from SGR1806-20
  9. IPN triangulation of GRB030717 (annulus)
  10. RXTE PCA Observations of SGR1806-20 Region
  11. GRB030329: Subaru Optical Spectroscopy
  12. Triangulation of GRB030715 (single large error box)
  13. Triangulation of GRB030714 (single large error box)
  14. 030716 NOT a GRB
  15. IPN triangulation of GRB030714 (two large error boxes)
  16. IPN triangulation of GRB030715 (two large error boxes)
  17. GRB030329: RTT150 optical observations
  18. GRBlog: Compilation of all GCN Circ. data
  19. IPN detection of renewed activity from SGR1806-20
  20. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  21. IPN triangulation of GRB030710 (annulus)
  22. IPN triangulation of GRB030709 (annulus)
  23. GRB030706 triangulation (single large error box)
  24. IPN triangulation of GRB030706 (annulus)
  25. IPN triangulation of GRB030629 (annulus)
  26. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  27. 030629 NOT a real GRB
  28. GRB030329, optical observation in May
  29. IPN triangulation of GRB030626 (single large error box)
  30. IPN triangulation of GRB030626 (two large error boxes)
  31. GRB030329: second XMM-Newton observation
  32. GRB030418: R optical observations
  33. HETE detection of burst from SGR1806-20
  34. GRB030329 -- RATAN-600 data in April-May
  35. Final IPN error ellipse for GRB021206 (the polarized GRB)
  36. GRB 021206, Radio afterglow candidate
  37. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  38. IPN triangulation of GRB030607 (annulus)
  39. IPN triangulation of GRB030606 (two alternate error boxes)
  40. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  41. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  42. IPN triangulation of GRB030605B (annulus)
  43. GRB 030528: Optical Observations
  44. IPN triangulation of GRB030605 (annulus)
  45. GRB 030528: tentative NIR counterpart
  46. GRB 030528, radio observations
  47. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  48. GRB030329, further radio observations at GMRT
  49. GRB030528, BVRI field photometry
  50. IPN triangulation of GRB030601 (annulus)
  51. GRB030329, SPM optical observations
  52. GRB030528: Chandra TOO Planned
  53. GRB 030519B: optical observations.
  54. MASTER: optical observation GRB030601
  55. GRB030528(=H2724): Revised SXC Localization
  56. GRB 030329: optical observations
  57. GRB 030329/SN 2003dh: Jitter Episode
  58. GRB 030528, Teramo optical observation
  59. GRB 030528 Bisei optical observation
  60. GRB030528 (H2724): A long GRB localized by HETE
  61. GRB 030329: Correction to GCN 2254
  62. GRB 030329: Optical Observations
  63. GRB 030528: Optical observations at RIKEN
  64. GRB 030528 (=H2724) Kyoto optical observation
  65. IPN triangulation of GRB030523B (annulus)
  66. GRB 030416: Optical Observations
  67. GRB 030329: Planned XMM-Newton Observation
  68. IPN triangulation of GRB030523 (annulus)
  69. GRB 030329: optical photometry at various french observatories
  70. GRB 030329: optical photometry at Belesta observatory (France)
  71. GRB030329, Optical observations
  72. GRB 030329/SN 2003dh: Possible increase in brightness
  73. GRB 030329: HST ACS Observations of the Host
  74. GRB 030329 Optical Observations
  75. GRB030329: XMM-Newton observation
  76. GRB 021004: HST observations
  77. GRB030324: Further Observations of the Candidate Optical Afterglow
  78. GRB030519B (=H2716): Peak Fluxes, Fluences, and Energy Spectrum
  79. IPN triangulation of GRB030519B=H2716 (small error box)
  80. GRB 030418: Second Epoch Optical Observations with Magellan
  81. GRB030519B (=H2716): A Long, Bright GRB Localized by the HETE WXM
  82. IPN triangulation of GRB030519 (annulus)
  83. IPN triangulation of GRB030518C (annulus)
  84. IPN triangulation of GRB030518B (annulus)
  85. IPN triangulation of GRB030518A (annulus)
  86. IPN triangulation of GRB030514 (annulus)
  87. HETE GRB030329, correction to Rc Observations in Loiano
  88. IPN triangulation of GRB030513 (annulus)
  89. IPN triangulation of GRB030509B (annulus)
  90. GRB 030329: Optical limit (contemporaneous imaging)
  91. GRB 030501: final TAROT limits
  92. IPN triangulation of GRB030509 (small errror box)
  93. IPN triangulation of GRB030509 - correction
  94. IPN triangulation of GRB030509 (single error box)
  95. GRB030329: RTT150 optical observations
  96. GRB030329, BVRI photometry
  97. GRB030429, refiend optical brightness
  98. GRB 030329: Optical limit (contemporaneous photography)
  99. GRB030418, BVRcIc field photometry
  100. GRB 030429: Redshift of neighbor galaxy

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