The<i>XMM–Newton</i>view of the central degrees of the Milky Way

Ponti, G.; Morris, Mark; Terrier, R.; Haberl, F.; Sturm, R.; Clavel, M.; Soldi, S.; Goldwurm, A.; Predehl, P.; Nandra, K.; Bélanger, G.; Warwick, R. S.; Tatischeff, V.

doi:10.1093/mnras/stv1331

Cited by 113 publications

(151 citation statements)

References 237 publications

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“…The group-1 and 2 sources are marked in green and yellow, respectively and they are labeled with the NuSTAR source IDs. Some of the molecular clouds and the X-ray filaments are marked with red ellipses and magenta polygons, respectively (see Ponti et al 2015a). The yellow arrows point the three hard X-ray sources without clear soft X-ray counterparts (Section 6.1).…”

Section: Discussionmentioning

confidence: 99%

“…In particular, NGP 59 is located at the southern end of the small (11″×6 5) X-ray filament, G0.007-0.014 (Johnson et al 2009;Ponti et al 2015b). According to Johnson et al (2009), the soft (<10 keV) X-ray spectrum of the filament has a photon index of G S ∼ 1 for a power-law model (albeit with a large uncertainty) and the 2-10 keV luminosity is ∼2×10…”

Section: Discussionmentioning

confidence: 99%

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NuSTAR HARD X-RAY SURVEY OF THE GALACTIC CENTER REGION. II. X-RAY POINT SOURCES

Hong

Mori

Hailey

et al. 2016

ApJ

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We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg 2 region around SgrA * with a total exposure of 1.7 Ms, and 7 sources in the SgrB2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ∼4× and ∼8×10 32 erg s -1 at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the SgrA diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction (>40%-60%). Both spectral analysis and logN-logS distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT>20 keV on average for a single temperature thermal plasma model or an average photon index of Γ=1.5-2 for a power-law model. These findings suggest that the GC X-ray source population may contain a larger fraction of XBs with high plasma temperatures than the field population.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

NuSTAR HARD X-RAY SURVEY OF THE GALACTIC CENTER REGION. II. X-RAY POINT SOURCES

Hong

Mori

Hailey

et al. 2016

ApJ

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“…More recently, another SNR candidate has been identified in the SGR A's bipolar radio/X-ray Lobes (Ponti et al 2015). This SNR appears symmetric around the GC, its center almost coincides with SGR A* and its radius is approximately 12 pc.…”

Section: Observationsmentioning

confidence: 96%

“…Two SNRs have been detected near the GC: SGR East (Mezger et al 1989;Baganoff et al 2003) and SGR A's bipolar radio/X-ray Lobes (Ponti et al 2015). Two neutron stars have also been detected close to the GC: CX-OGC J174545.5-285829 (a.k.a.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Supernova Remnants Near the Galactic Center

Yalinewich

Piran

Sari

2017

ApJ

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Supernovae near the galactic center evolve differently from regular galactic supernovae. This is mainly due to the environment into which the supernova remnants propagate. Instead of a static, uniform density medium, SNRs near the galactic center propagate into a wind swept environment with a velocity away from the galactic center, and a graded density profile. This causes these SNRs to be non -spherical, and to evolve faster than their galactic counterparts. We develop an analytic theory for the evolution of explosions within a stellar wind, and verify it using a hydrodynamic code. We show that such explosions can evolve in one of three possible morphologies. Using these results we discuss the association between the two SNRs (SGR East and SGR A's bipolar radio/X-ray Lobes) and the two neutron stars (the cannonball and SGR J1745-2900) near the galactic center. We show that, given the morphologies of the SNR and positions of the neutron stars, the only possible association is between SGR A's bipolar radio/X-ray Lobes and SGR J1745-2900. The compact object created in the explosion of SGR East remains undetected, and the SNR of the supernova that created the cannonball has already disappeared.

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“…It has been suggested that overluminous HCN could be due to X-ray chemistry (Lepp & Dalgarno 1996;Meijerink et al 2007;Harada et al 2013). While several regions of enhanced emission are associated with X-ray sources (GCM-0.02-0.07 borders a supernova remnant, and clouds in the GCM0.11-0.08 complex are observed to have a propagating X-ray light echo Ponti et al 2010) that may also be related to enhanced SiO in these regions (Martín-Pintado et al 2000), there is no X-ray emission associated with the bright extended HCN 1-0 emission north of Sgr D (Ponti et al 2015). We also investigate whether the enhanced HCN 1-0 is correlated with infrared emission.…”

Section: Variation In Conditions In the Local Environmentmentioning

confidence: 99%

Origins of Scatter in the Relationship Between HCN 1-0 and Dense Gas Mass in the Galactic Center

Mills

Battersby

2017

ApJ

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We investigate the correlation of HCN 1-0 with gas mass in the central 300 pc of the Galaxy. We find that on the ∼ 10 pc size scale of individual cloud cores, HCN 1-0 is well correlated with dense gas mass when plotted as a log-log relationship. There is ∼0.75 dex of scatter in this relationship from clouds like Sgr B2, which has an integrated HCN 1-0 intensity of a cloud less than half its mass, and others that have HCN 1-0 enhanced by a factor of 2-3 relative to clouds of comparable mass. We identify the two primary sources of scatter to be self-absorption and variations in HCN abundance. We also find that the extended HCN 1-0 emission is more intense per unit mass than in individual cloud cores. In fact the majority (80%) of HCN 1-0 emission comes from extended gas with column densities below 7 × 10 22 cm −2 , accounting for 68% of the total mass. We find variations in the brightness of HCN 1-0 would only yield a ∼ 10% error in the dense gas mass inferred from this line in the Galactic center. However, the observed order of magnitude HCN abundance variations, and the systematic nature of these variations, warn of potential biases in the use of HCN as dense gas mass tracer in more extreme environments such as AGN and shock-dominated regions. We also investigate other 3 mm tracers, finding that HNCO is better correlated with mass than HCN, and might be a better tracer of cloud mass in this environment.

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TheXMM–Newtonview of the central degrees of the Milky Way

Cited by 113 publications

References 237 publications

NuSTAR HARD X-RAY SURVEY OF THE GALACTIC CENTER REGION. II. X-RAY POINT SOURCES

NuSTAR HARD X-RAY SURVEY OF THE GALACTIC CENTER REGION. II. X-RAY POINT SOURCES

Evolution of Supernova Remnants Near the Galactic Center

Origins of Scatter in the Relationship Between HCN 1-0 and Dense Gas Mass in the Galactic Center

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