Identified particle production, azimuthal anisotropy, and interferometry measurements in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Au</mml:mi><mml:mo>+</mml:mo><mml:mi mathvariant="normal">Au</mml:mi></mml:mrow></mml:math>collisions at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:msub><mml:mi>s</mml:mi><mml:mrow><mml:mi mathvariant="italic">NN</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>9</mml:mn><mml:mo>.</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:math>GeV

We present the first measurements of identified hadron production, azimuthal anisotropy, and pion interferometry from $\mathrm{Au}+\mathrm{Au}$ collisions below the nominal injection energy at the BNL Relativistic Heavy-Ion Collider (RHIC) facility. The data were collected using the large acceptance solenoidal tracker at RHIC (STAR) detector at $\sqrt{{s}_{\mathit{NN}}}=9.2$ GeV from a test run of the collider in the year 2008. Midrapidity results on multiplicity density $\mathit{dN}/\mathit{dy}$ in rapidity $y$, average transverse momentum $\ensuremath{\langle}{p}_{T}\ensuremath{\rangle}$, particle ratios, elliptic flow, and Hanbury-Brown--Twiss (HBT) radii are consistent with the corresponding results at similar $\sqrt{{s}_{\mathit{NN}}}$ from fixed-target experiments. Directed flow measurements are presented for both midrapidity and forward-rapidity regions. Furthermore the collision centrality dependence of identified particle $\mathit{dN}/\mathit{dy}$, $\ensuremath{\langle}{p}_{T}\ensuremath{\rangle}$, and particle ratios are discussed. These results also demonstrate that the capabilities of the STAR detector, although optimized for $\sqrt{{s}_{\mathit{NN}}}=200$ GeV, are suitable for the proposed QCD critical-point search and exploration of the QCD phase diagram at RHIC.