Abstract
We present the results of Suzaku and XMM-Newton X-ray observations of the cluster pair 1E2216.0-0401 and 1E2215.7-0404. We discover an X-ray bridge between the clusters. Suzaku and XMM-Newton observations revealed that each cluster hosts gas with moderate temperature of kT0401 = 4.8 ± 0.1 keV and kT0404 = 5.8 ± 0.2 keV, respectively. On the other hand, the bridge region shows a remarkably high temperature (kT = 6.6 ± 0.5 keV). Furthermore, at the position of the bridge, we detected an enhancement in the wavelet-decomposed soft-band (0.5-4.0 keV) XMM-Newton image at 3 sigma significance, this is most likely due to a compression of the intracluster medium (ICM) as a consequence of the merging activity. This X-ray intensity and temperature enhancement are not consistent with those expected from a late phase, but are in agreement with the predictions by numerical simulations of an early phase merger. From the temperature jump at the location of the bridge, the Mach number is estimated to be M = 1.4 ± 0.1, which corresponds to a shock propagation velocity of about 1570 km s-1. From the shock properties, we estimate that core-passage will occur in 0.3-0.6 Gyr and that the age of the shock structure is 50-100 Myr. Based on the measured properties of the ICM at the bridge and estimation of timescales, we find indications for non-equilibrium ionization. We also discover possible diffuse radio emission located between the merging clusters. Combining the radio, X-ray, and optical image data, we speculate that the detected radio sources are most likely related to the merger event. Thus, 1E2216.0-0401 and 1E2215.7-0404 is a new example of an early phase cluster merger with remarkable characteristics.
| Original language | English |
|---|---|
| Article number | L7 |
| Number of pages | 5 |
| Journal | Astronomy and Astrophysics |
| Volume | 593 |
| Early online date | 8 Sep 2016 |
| DOIs | |
| Publication status | E-pub ahead of print - 8 Sep 2016 |
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Keywords
- galaxies
- clusters
- X-Rays
- shock waves
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Suzaku and XMM-Newton observations of the newly discovered early-stage cluster merger of 1E2216.0-0401 and 1E2215.7-0404. / Akamatsu, H.; Gu, L.; Shimwell, T. W.; Mernier, F.; Mao, J.; Urdampilleta, I.; de Plaa, J.; Röttgering, H. J. A.; Kaastra, J. S.
In: Astronomy and Astrophysics, Vol. 593, L7, 08.09.2016.Research output: Contribution to journal › Article
TY - JOUR
T1 - Suzaku and XMM-Newton observations of the newly discovered early-stage cluster merger of 1E2216.0-0401 and 1E2215.7-0404
AU - Akamatsu, H.
AU - Gu, L.
AU - Shimwell, T. W.
AU - Mernier, F.
AU - Mao, J.
AU - Urdampilleta, I.
AU - de Plaa, J.
AU - Röttgering, H. J. A.
AU - Kaastra, J. S.
PY - 2016/9/8
Y1 - 2016/9/8
N2 - We present the results of Suzaku and XMM-Newton X-ray observations of the cluster pair 1E2216.0-0401 and 1E2215.7-0404. We discover an X-ray bridge between the clusters. Suzaku and XMM-Newton observations revealed that each cluster hosts gas with moderate temperature of kT0401 = 4.8 ± 0.1 keV and kT0404 = 5.8 ± 0.2 keV, respectively. On the other hand, the bridge region shows a remarkably high temperature (kT = 6.6 ± 0.5 keV). Furthermore, at the position of the bridge, we detected an enhancement in the wavelet-decomposed soft-band (0.5-4.0 keV) XMM-Newton image at 3 sigma significance, this is most likely due to a compression of the intracluster medium (ICM) as a consequence of the merging activity. This X-ray intensity and temperature enhancement are not consistent with those expected from a late phase, but are in agreement with the predictions by numerical simulations of an early phase merger. From the temperature jump at the location of the bridge, the Mach number is estimated to be M = 1.4 ± 0.1, which corresponds to a shock propagation velocity of about 1570 km s-1. From the shock properties, we estimate that core-passage will occur in 0.3-0.6 Gyr and that the age of the shock structure is 50-100 Myr. Based on the measured properties of the ICM at the bridge and estimation of timescales, we find indications for non-equilibrium ionization. We also discover possible diffuse radio emission located between the merging clusters. Combining the radio, X-ray, and optical image data, we speculate that the detected radio sources are most likely related to the merger event. Thus, 1E2216.0-0401 and 1E2215.7-0404 is a new example of an early phase cluster merger with remarkable characteristics.
AB - We present the results of Suzaku and XMM-Newton X-ray observations of the cluster pair 1E2216.0-0401 and 1E2215.7-0404. We discover an X-ray bridge between the clusters. Suzaku and XMM-Newton observations revealed that each cluster hosts gas with moderate temperature of kT0401 = 4.8 ± 0.1 keV and kT0404 = 5.8 ± 0.2 keV, respectively. On the other hand, the bridge region shows a remarkably high temperature (kT = 6.6 ± 0.5 keV). Furthermore, at the position of the bridge, we detected an enhancement in the wavelet-decomposed soft-band (0.5-4.0 keV) XMM-Newton image at 3 sigma significance, this is most likely due to a compression of the intracluster medium (ICM) as a consequence of the merging activity. This X-ray intensity and temperature enhancement are not consistent with those expected from a late phase, but are in agreement with the predictions by numerical simulations of an early phase merger. From the temperature jump at the location of the bridge, the Mach number is estimated to be M = 1.4 ± 0.1, which corresponds to a shock propagation velocity of about 1570 km s-1. From the shock properties, we estimate that core-passage will occur in 0.3-0.6 Gyr and that the age of the shock structure is 50-100 Myr. Based on the measured properties of the ICM at the bridge and estimation of timescales, we find indications for non-equilibrium ionization. We also discover possible diffuse radio emission located between the merging clusters. Combining the radio, X-ray, and optical image data, we speculate that the detected radio sources are most likely related to the merger event. Thus, 1E2216.0-0401 and 1E2215.7-0404 is a new example of an early phase cluster merger with remarkable characteristics.
KW - galaxies
KW - clusters
KW - X-Rays
KW - shock waves
UR - http://www.scopus.com/inward/record.url?scp=84986286549&partnerID=8YFLogxK
UR - https://arxiv.org/abs/1608.01669
U2 - 10.1051/0004-6361/201629275
DO - 10.1051/0004-6361/201629275
M3 - Article
VL - 593
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - L7
ER -