8 papers
Evidence of Nuclear Urca Process in the Ocean of Neutron-Star Superburst MAXI J1752457
Hao Huang, Akira Dohi, Amira Aoyama +2
We propose that the rapid cooling of the neutron star following its X-ray superburst in MAXI J1752457 over a period of 4 days, observed by two Japanese satellites, MAXI and Ninj…
In-orbit Demonstration of X-ray Pulsar Navigation with NinjaSat
Naoyuki Ota, Takuya Takahashi, Toru Tamagawa +26
This study demonstrated the pulsar navigation capability of the CubeSat X-ray observatory NinjaSat, which is equipped with two Gas Multiplier Counters (GMCs). The GMCs are sensitiv…
Unveiling the Nature of Superorbital Modulation of SMC X-1 using NinjaSat
Chin-Ping Hu, Naoyuki Ota, Takuya Takahashi +13
We report a long-term, high-cadence timing and spectral observation of the X-ray pulsar SMC X-1 using NinjaSat, a 6U CubeSat in low-Earth orbit, covering nearly a full superorbital…
Return of the Clocked Burster: Exceptionally Short Recurrence Time in GS 1826-238
Tomoshi Takeda, Toru Tamagawa, Teruaki Enoto +15
We report the discovery of an exceptionally short burst recurrence time in the well-known clocked burster GS 1826238, observed with the CubeSat X-ray observatory NinjaSat. In 20…
Thermonuclear superburst of MAXI J1752457 observed with NinjaSat and MAXI
Amira Aoyama, Teruaki Enoto, Takuya Takahashi +17
An uncatalogued bright X-ray transient was detected with MAXI on November 9, 2024, named MAXI J1752457. The NinjaSat X-ray observatory promptly observed the source from November…
NinjaSat monitoring of Type-I X-ray bursts from the clocked burster SRGA J144459.2604207
Tomoshi Takeda, Toru Tamagawa, Teruaki Enoto +25
The CubeSat X-ray observatory NinjaSat was launched on 2023 November 11 and has provided opportunities for agile and flexible monitoring of bright X-ray sources. On 2024 February 2…