Probing the Warm and Hot Absorbers along the Sightline of PG 0052+251

Abstract We analyze the absorption features in the public 73 ks XMM-Newton spectra of the Seyfert 1 galaxy PG 0052+251. Our analysis reveals the presence of a warm absorber (WA) intrinsic to the source and the hot circumgalactic medium at zero redshift. The identified WA is inflowing toward the central black hole, with a velocity shift of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>117</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>8</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>171</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>156</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> km s −1 . The ionization parameter of the WA is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mi>ξ</mml:mi> <mml:mo>/</mml:mo> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">erg</mml:mi> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">cm</mml:mi> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:mn>1.1</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.19</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.17</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> , showing strong O ii and O iii absorption lines, along with a significant absorption of the spectral continuum at ≳10 Å. The line of sight toward PG 0052+251 intersects the halo of M31 at an impact parameter of approximately 218 kpc. Several local ( z ∼ 0) absorption lines, like O vii , O viii , and Ne ix , were detected. The derived hydrogen column density of the local hot gas is 2.2–2.6 σ higher than those estimated by several models of the Galactic hot halo, suggesting a likely contribution from the M31 halo. We also find two absorption features at 24.305 Å and 21.410 Å, which are unlikely to be associated with the hot halos or the warm-hot intergalactic medium but imply the presence of an additional WA component with an outflow velocity of approximately −7000 km s −1 .