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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"

32531 results found.

  1. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  2. XRF 030824: additional observations at CFHT
  3. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  4. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  5. XRF 030723: Subaru Optical Observations
  6. XRF 030824: Early follow-up observation at Kiso observatory
  7. XRF 030723: Detection of the likely host galaxy
  8. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  9. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  10. IPN triangulation of GRB030922A (large error box)
  11. IPN triangulation of GRB030921 (large error box)
  12. GRB030913: Subaru Optical Observations
  13. GRB 030913: ROTSE-3c Optical Observations
  14. GRB030913: OT's limit by MASTER
  15. GRB030913, candidate afterglow observations
  16. GRB030913: AAVSO optical observations
  17. GRB030913 (=H2849): Confirmation of the Flight Localization
  18. GRB030913 (=H2849): TAROT Observations
  19. Magellan Observations of GRB030725 (=H2779)
  20. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  21. IBAS detection of bursts from SGR 1806-20
  22. Radio Observations of SGR1806-20
  23. GRB 030824: Candidate Follow-Up
  24. XRF030824: Second-epoch Palomar observations
  25. XRF030824: optical observations
  26. XRF030824: Palomar observations
  27. GRB030823: optical observation at Tokyo Tech
  28. RAPTOR observations of GRB030823
  29. IPN triangulation of GRB030821 (=H2814; refined error box)
  30. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  31. Summary of recent IPN and HETE detections of SGR bursts
  32. Clarification of GCN 2354 on SGR1806-20
  33. IPN detection of continued activity from SGR1806-20
  34. 030813 SGR event (Konus-Wind observation)
  35. SGR 1808-20 (=H2802): A Possible new SGR
  36. GRB 021206 Optical Observations
  37. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  38. IPN/HETE summary of recent bursts from SGR1806-20
  39. XRF 030723: Detection of a rebrightening in the optical afterglow
  40. GRB030725: Optical observations
  41. XRF030723, BVRcIc field photometry update
  42. GRB021206 optical counterpart upper limit
  43. XRF030723: Re-analysis of ROTSE-III early images
  44. IPN triangulation of GRB030725 (=H2779; small error box)
  45. XRF030723 (=H2777): Second Epoch Magellan Observations
  46. GRB 030725: optical observations.
  47. GRB030725, optical transient observations
  48. XRF030723 Radio Observations
  49. XRF 030723: confirmation of fading optical counterpart
  50. XRF030723(=H2777): Chandra Observations
  51. XRF 030723: VLT spectra
  52. Magellan Observations of XRF030723 (=H2777)
  53. GRB030723: Upper limits from historical observations
  54. GRB030725, possible optical transient
  55. XRF030723: Palomar observations and proposed counterpart
  56. GRB030725 (=H2779): A Bright GRB Localized by HETE
  57. XRF030723: optical observations
  58. XRF030723 (= H2777): Chandra Observations Scheduled
  59. XRF030723, BVRcIc field photometry
  60. XRF030723, optical observations
  61. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  62. Konus-Wind detection of the bursts from SGR1806-20 region
  63. SGR 1806-20, submm observations
  64. RXTE PCA Observations of SGR1806-20 Region
  65. GRB030329: Subaru Optical Spectroscopy
  66. Triangulation of GRB030715 (single large error box)
  67. Triangulation of GRB030714 (single large error box)
  68. GRB030329: RTT150 optical observations
  69. GRBlog: Compilation of all GCN Circ. data
  70. GRB030706 triangulation (single large error box)
  71. GRB030329, optical observation in May
  72. IPN triangulation of GRB030626 (single large error box)
  73. GRB030418: R optical observations
  74. Final IPN error ellipse for GRB021206 (the polarized GRB)
  75. GRB 021206, Radio afterglow candidate
  76. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  77. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  78. GRB 030528: Optical Observations
  79. GRB 030528: tentative NIR counterpart
  80. GRB 030528, radio observations
  81. GRB030329, further radio observations at GMRT
  82. GRB030528, BVRI field photometry
  83. GRB030329, SPM optical observations
  84. GRB030528: Chandra TOO Planned
  85. GRB 030519B: optical observations.
  86. GRB 030329: optical observations
  87. GRB 030329/SN 2003dh: Jitter Episode
  88. GRB 030528, Teramo optical observation
  89. GRB 030528 Bisei optical observation
  90. GRB030528 (H2724): A long GRB localized by HETE
  91. GRB 030329: Correction to GCN 2254
  92. GRB 030329: Optical Observations
  93. GRB 030416: Optical Observations
  94. GRB030329, Optical observations
  95. GRB 030329/SN 2003dh: Possible increase in brightness
  96. GRB 030329: HST ACS Observations of the Host
  97. GRB 030329 Optical Observations
  98. GRB030329: XMM-Newton observation
  99. GRB030324: Further Observations of the Candidate Optical Afterglow
  100. GRB030519B (=H2716): Peak Fluxes, Fluences, and Energy Spectrum

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