Investigating the Lower Mass Gap with Low Mass X-ray Binary Population Synthesis

<p>Title: Investigating the Lower Mass Gap with Low Mass X-ray Binary Population Synthesis&nbsp;</p> <p>Authors: Jared C. Siegel, Ilia Kiato, Vicky Kalogera, Christopher P. L. Berry,<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Thomas J. Maccarone, Katelyn Breivik, Jeff J. Andrews, Simone S. Bavera,<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Aaron Dotter, Tassos Fragos, Konstantinos Kovlakas, Devina Misra,<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Kyle A. Rocha, Philipp M. Srivastava, Meng Sun, Zepei Xing,<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;and Emmanouil Zapartas<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<br> Table: Summary of Population Synthesis Models</p> <p>Columns:<br> &nbsp; &nbsp; Population parameters:<br> &nbsp; &nbsp; &nbsp; &nbsp; CE: efficiency of common envelope unbinding, either:<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; * 1 or 5<br> &nbsp; &nbsp; &nbsp; &nbsp; CE merge: stars without a distinct core-envelope boundary that instigate a CE&nbsp;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; event are either assumed to survive the CE (Optimistic) or are&nbsp;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; assumed to merge (Pessimistic).<br> &nbsp; &nbsp; &nbsp; &nbsp; QMIN: minimum ZAMS ratio, either:<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; * 0.01<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; * Lifetime limited (pre-main-sequence lifetime of the secondary is shorter<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; than the main-sequence lifetime of the primary)<br> &nbsp; &nbsp; &nbsp; &nbsp; BRK: prescription for magnetic braking of a tidally coupled magnetic wind, either:<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; * H02: Hurley et al. 2002<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; * IT03: Ivanova &amp; Taam 2003<br> &nbsp; &nbsp; &nbsp; &nbsp; ACC: amount of mass accreted during Roche-lobe overflow, either:<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; * 50% efficiency<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; * State dependent: (i) limited to ten-times the thermal rate if the accretor is a main-sequence,&nbsp;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Hertzsprung gap or core helium burning star, or (ii) unlimited if the accretor is a giant branch,&nbsp;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; early asymptotic giant branch or asymptotic giant branch star.&nbsp;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Compact objects also experience conservative mass transfer, provided the&nbsp;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; mass-transfer rate is sub-Eddington.<br> &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<br> &nbsp; &nbsp; Selection effect parameters:<br> &nbsp; &nbsp; &nbsp; &nbsp; weighting: logs what selection effects were considered for the detection weighted results, either:<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; *prob_occ: the probability that an outburst occurs and turns off during the survey<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; *prob_see: the probability that the outburst is bright enough to be detected<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; *prob: the product of prob_occ and prob_see<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<br> &nbsp; &nbsp; &nbsp; &nbsp; RIA_nu: determines when the transition to radiatively inefficient accretion occurs, either:<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; *0 (no transition) or 0.05<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<br> &nbsp; &nbsp; Results:<br> &nbsp; &nbsp; &nbsp; &nbsp; f_gap_N: fraction of LMXB systems with a mass gap BH (M&lt;4.5Msol)<br> &nbsp; &nbsp; &nbsp; &nbsp; f_AIC_N: fraction of LMXB systems where the BH formed through accretion induced collapse of a NS<br> &nbsp; &nbsp; &nbsp; &nbsp; f_AIC_gap_N: fraction of LMXB systems where the BH formed through accretion induced collapse of a NS and<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;the BH is in the mass gap<br> &nbsp; &nbsp; &nbsp; &nbsp; fw_X_N: detection weighted fraction of X (e.g., gap, AIC, AIC_gap)<br> &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<br> Notes:<br> &nbsp; &nbsp; &nbsp;Each quantity is calculated for 5000 snapshots of the evolution tracks.&nbsp;<br> &nbsp; &nbsp; &nbsp;Here we report the Nth percentiles (e.g., 16, 50, 84) of each quantity.</p>